Monday, September 30, 2019

Typology of semantic change (Open problems in computational diversity linguistics 8)


With this month's problem we are leaving the realm of modeling, which has been the basic aspect underlying the last three problems, discussed in June, July, and August, and enter the realm of typology, or general linguistics. The last three problems that I will discuss, in this and two follow-up posts, deal with the basic problem of making use or collecting data that allows us to establish typologies, that is, to identify cross-linguistic tendencies for specific phenomena, such as semantic change (this post), sound change (October), or semantic promiscuity (November).

Cross-linguistic tendencies are here understood as tendencies that occur across all languages independently of their specific phylogenetic affiliation, the place where they are spoken, or the time when they are spoken. Obviously, the uniformitarian requirement of independence of place and time is an idealization. As we know well, the capacity for language itself developed, potentially gradually, with the evolution of modern humans, and as a result, it does not make sense to assume that the tendencies of semantic change or sound change were the same through time. This has, in fact, been shown in recent research that illustrated that there may be a certain relationship between our diet and the speech sounds that we speak in our languages (Blasi et al. 2019).

Nevertheless, in the same way in which we simplify models in physics, as long as they yield good approximations of the phenomena we want to study, we can also assume a certain uniformity for language change. To guarantee this, we may have to restrict the time frame of language development that we want to discuss (eg. the last 2,000 years), or the aspects of language we want to investigate (eg. a certain selection of concepts that we know must have been expressed 5,000 years ago).

For the specific case of a semantic change, the problem of establishing a typology of the phenomenon can thus be stated as follows:
Assuming a certain pre-selection of concepts that we assume were readily expressed in a given time frame, establish a general typology that informs about the universal tendencies by which a word expressing one concept changes its meaning, to later express another concept in the same language.
In theory, we can further relax the conditions of universality and add the restrictions on time and place later, after having aggregated the data. Maybe this would even be the best idea for a practical investigation; but given that the time frames in which we have attested data for semantic changes are rather limited, I do not believe that it would make much of a change.

Why it is hard to establish a typology of semantic change

There are three reasons why it is hard to establish a typology of semantic change. First, there is the problem of acquiring the data needed to establish the typology. Second, there is the problem of handling the data efficiently. Third, there is the problem of interpreting the data in order to identify cross-linguistic, universal tendencies.

The problem of data acquisition results from the fact that we lack data on observed processes of semantic change. Since there are only a few languages with a continuous tradition of written records spanning 500 years or more, we will never be able to derive any universal tendencies from those languages alone, even if it may be a good starting point to start from languages like Latin and its Romance descendants, as has been shown by Blank (1997).

Accepting the fact that processes attested only for Romance languages are never enough to fill the huge semantic space covered by the world's languages, the only alternative would be using inferred processes of semantic change — that is, processes that have been reconstructed and proposed in the literature. While it is straightforward to show that the meanings of cognate words in different languages can vary quite drastically, it is much more difficult to infer the direction underlying the change. Handling the direction, however, is important for any typology of semantic change, since the data from observed changes suggests that there are specific directional tendencies. Thus, when confronted with cognates such as selig "holy" in German and silly in English, it is much less obvious whether the change happened from "holy" to "silly" or from "silly" to "holy", or even from an unknown ancient concept to both "holy" and "silly".

As a result, we can conclude that any collection of data on semantic change needs to make crystal-clear upon which types of evidence the inference of semantic change processes is based. Citing only the literature on different language families is definitely not enough. Because of the second problem, this also applies to the handling of data on semantic shifts. Here, we face the general problem of elicitation of meanings. Elicitation refers to the process in fieldwork where scholars use a questionnaire to ask their informants how certain meanings are expressed. The problem here is that linguists have never tried to standardize which meanings they actually elicit. What they use, instead, are elicitation glosses, which they think are common enough to allow linguists to understand to what meaning they refer. As a result, it is extremely difficult to search in field work notes, and even in wordlists or dictionaries, for specific meanings, since every linguist is using their own style, often without further explanations.

Our Concepticon project (List et al. 2019, https://concepticon.clld.org) can be seen as a first attempt to handle elicitation glosses consistently. What we do is to link those elicitation glosses that we find in questionnaires, dictionaries, and fieldwork notes to so-called concept sets, which reflect a given concept that is given a unique identifier and a short definition. It would go too far to dive deeper into the problem of concept handling. Interested readers can have a look at a previous blog post I wrote on the topic (List 2018). In any case, any typology on semantic change will need to find a way to address the problem of handling elicitation glosses in the literature, in the one or the other way.

As a last problem, when having assembled data that show semantic change processes across a sufficiently large sample of languages and concepts, there is the problem of analyzing the data themselves. While it seems obvious to identify cross-linguistic tendencies by looking for examples that occur in different language families and different parts of the world, it is not always easy to distinguish between the four major reasons for similarities among languages, namely: (1) coincidence, (2) universal tendencies, (3) inheritance, and (4) contact (List 2019). The only way to avoid being forced to make use of potentially unreliable statistics, to squeeze out the juice of small datasets, is to work on a sufficiently large coverage of data from as many language families and locations as possible. But given that there are no automated ways to infer directed semantic change processes across linguistic datasets, it is unlikely that a collection of data acquired from the literature alone will reach the critical mass needed for such an endeavor.

Traditional approaches

Apart from the above-mentioned work by Blank (1997), which is, unfortunately, rarely mentioned in the literature (potentially because it is written in German), there is an often-cited paper by Wilkinson (1996), and preliminary work on directionality (Urban 2012). However, the attempt that addresses the problem most closely is the Database of Semantic Shifts (Zalizniak et al. 2012), which has, according to the most recent information on the website, was established in 2002 and has been  continuously updated since then.

The basic idea, as far as I understand the principle of the database, is to collect semantic shifts attested in the literature, and to note the type of evidence, as well as the direction, where it is known. The resource is unique, nobody else has tried to establish a collection of semantic shifts attested in the literature, and it is therefore incredibly valuable. It shows, however, also, what problems we face when trying to establish a typology of semantic shifts.

Apart from the typical technical problems found in many projects shared on the web (missing download access to all data underlying the website, missing deposit of versions on public repositories, missing versioning), the greatest problem of the project is that no apparent attempt was undertaken to standardize the elicitation glosses. This became specifically obvious when we tried to link an older version of the database, which is now no longer available, to our Concepticon project. In the end, I selected some 870 concepts from the database, which were supported by more datapoints, but had to ignore more than 1500 remaining elicitation glosses, since it was not possible to infer in reasonable time what the underlying concepts denote, not to speak of obvious cases where the same concept was denoted by slightly different elicitation glosses. As far as I can tell, this has not changed much with the most recent update of the database, which was published some time earlier this year.

Apart from the afore-mentioned problems of missing standardization of elicitation glosses, the database does not seem to annotate which type of evidence has been used to establish a given semantic shift. An even more important problem, which is typical of almost all attempts to establish databases of change in the field of diversity linguistics, is that the database only shows what has changed, while nothing can be found on what has stayed the same. A true typology of change, however, must show what has not changed along with showing what has changed. As a result, any attempt to pick proposed changes from the literature alone will fail to offer a true typology, a collection of universal tendencies

To be fair: the Database of Semantic Shifts is by no means claiming to do this. What it offers is a collection of semantic change phenomena discussed in the linguistic literature. This itself is an extremely valuable, and extremely tedious, enterprise. While I wish that the authors open their data, versionize it, standardize the elicitation glosses, and also host it on stable public archives, to avoid what happened in the past (that people quote versions of the data which no longer exist), and to open the data for quantitative analyses, I deeply appreciate the attempt to approach the problem of semantic change from an empirical, data-driven perspective. To address the problem of establishing a typology of semantic shift, however, I think that we need to start thinking beyond collecting what has been stated in the literature.

Computational approaches

As a first computational approach that comes in some way close to a typology of semantic shifts, there is the Database of Cross-Linguistic Colexifications (List et al. 2018), which was originally launched in 2014, and received a major update in 2018 (see List et al. 2018b for details). This CLICS database, which I have mentioned several times in the past, does not show diachronic data, ie. data on semantic change phenomena, but lists automatically detectable polysemies and homophonies (also called colexifications), instead.

While the approach taken by the Database of Semantic shifts is bottom-up in some sense, as the authors start from the literature and add those concept that are discussed there, CLICS is top-down, as it starts from a list of concepts (reflected as standardized Concepticon concept sets) and then checks which languages express more than one concept by one and the same word form.

The advantages of top-down approaches are: that much more data can be processed, and that one can easily derive a balanced sample in which the same concepts iare compared for as many languages as possible. The disadvantage is that such a database will ignore certain concepts a priori, if they do not occur in the data.

Since CLICS lists synchronic patterns without further interpreting them, the database is potentially interesting for those who want to work on semantic change, but it does not help solve the problem of establishing a typology of semantic change itself. In order to achieve this, one would have to go through all attested polysemies in the database and investigate them, searching for potential hints on directions.

A potential way to infer directions for semantic shifts is presented by Dellert (2016), who applies causal inference techniques on polysemy networks to address this task. The problem, as far as I understand the techniques, is that the currently available polysemy databases barely offer enough information needed for these kinds of analyses. Furthermore, it would also be important to see how well the method actually performs in comparison to what we think we already know about the major patterns of semantic change.

Initial ideas for improvement

There does not seem to be a practical way to address our problem by means of computational solutions alone. What we need, instead, is a computer-assisted strategy that starts from the base of  a thorough investigation of the criteria that scholars use to infer directions of semantic change from linguistic data. Once these criteria are settled, more or less, one would need to think of ways to operationalize them, in order to allow scholars to work with concrete etymological data, ideally comprising standardized word-lists for different language families, and to annotate them as closely as possible.

Ideally, scholars would propose larger etymological datasets in which they reconstruct whole language families, proposing semantic reconstructions for proto-forms. These would already contain the proposed directions of semantic change, and they would also automatically show where change does not happen. Since we currently lack automated workflows that fully account for this level of detail, one could start by applying methods for cognate detection across semantic semantic slots (cross-semantic cognate detection), which would yield valuable data on semantic change processes, without providing directions, and then adding the directional information based on the principles that scholars use in their reconstruction methodology.

Outlook

Given the recent advances in detection of sound correspondence patterns, sequence comparison, and etymological annotation in the field of computational historical linguistics, it seems perfectly feasible to work on detailed etymological datasets of the languages of the world, in which all information required to derive a typology of semantic change is transparently available. The problem is, however, that it would still take a lot of time to actually analyze and annotate these data, and to find enough scholars who would agree to carry out linguistic reconstruction in a similar way, using transparent tools rather than convenient shortcuts.

References

Blank, Andreas (1997) Prinzipien des lexikalischen Bedeutungswandels am Beispiel der romanischen Sprachen. Tübingen:Niemeyer.

Blasi, Damián E. and Steven Moran and Scott R. Moisik and Paul Widmer and Dan Dediu and Balthasar Bickel (2019) Human sound systems are shaped by post-Neolithic changes in bite configuration. Science 363.1192: 1-10.

List, Johann-Mattis and Simon Greenhill and Cormac Anderson and Thomas Mayer and Tiago Tresoldi and Robert Forkel (2018: CLICS: Database of Cross-Linguistic Colexifications. Version 2.0. Max Planck Institute for the Science of Human History. Jena: http://clics.clld.org/.

Johann Mattis List and Simon Greenhill and Christoph Rzymski and Nathanael Schweikhard and Robert Forkel (2019) Concepticon. A resource for the linking of concept lists (Version 2.1.0). Max Planck Institute for the Science of Human History. Jena: https://concepticon.clld.org/.

Dellert, Johannes and Buch, Armin (2016) Using computational criteria to extract large Swadesh Lists for lexicostatistics. In: Proceedings of the Leiden Workshop on Capturing Phylogenetic Algorithms for Linguistics.

List, Johann-Mattis and Greenhill, Simon J. and Anderson, Cormac and Mayer, Thomas and Tresoldi, Tiago and Forkel, Robert (2018) CLICS². An improved database of cross-linguistic colexifications assembling lexical data with help of cross-linguistic data formats. Linguistic Typology 22.2: 277-306.

List, Johann-Mattis (2018) Towards a history of concept list compilation in historical linguistics. History and Philosophy of the Language Sciences 5.10: 1-14.

List, Johann-Mattis (2019) Automated methods for the investigation of language contact situations, with a focus on lexical borrowing. Language and Linguistics Compass 13.e12355: 1-16.

Urban, Matthias (2011) Asymmetries in overt marking and directionality in semantic change. Journal of Historical Linguistics 1.1: 3-47.

Wilkins, David P. (1996) Natural tendencies of semantic change and the search for cognates. In: Durie, Mark (ed.) The Comparative Method Reviewed: Regularity and Irregularity in Language Change. New York: Oxford University Press, pp. 264-304.

Zalizniak, Anna A. and Bulakh, M. and Ganenkov, Dimitrij and Gruntov, Ilya and Maisak, Timur and Russo, Maxim (2012) The catalogue of semantic shifts as a database for lexical semantic typology. Linguistics 50.3: 633-669.

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