Cross-linguistic research is not easy because one needs to examine languages of diverse structures, but here I argue that typological classification is never “difficult”. The literature contains many references to such difficulties, but in fact, the main practical difficulty is obtaining complete data for a wide range of languages. And of course, one needs to find the right questions to ask if one wants to get interesting answers; but this is not a “difficulty” – it is the primary challenge of any kind of creative research enterprise.
Here are a few examples of passages where authors say that assigning languages or constructions to types is “difficult”. This list could be easily expanded.
Curnow (2000: 4): “there are a wide variety of issues here, such as the difficulty of … distinguishing analytically between an “inflectional” copula and a “zero” copula in languages with no verbal morphology”
Bickel & Nichols (2005): “unless tense, aspect, and mood were clearly distributed in distinct positions, we counted these as one category (thereby avoiding difficult decisions as to whether something is aspect or tense or mood)”
Dryer (2005): “Because it is difficult to distinguish verbal suffixes from clitics that can only attach to the verb, these are not distinguished here and morphemes which attach to the verb are all treated as instances of interrogative verb morphology, even if by some criteria they might be analysed as clitics.”
Iggesen (2005): “delimiting case markers from other morphological-functional entities is often particularly difficult in such languages”
Rijkhoff (2007: 711): “words were already categorized into distinct groups by ancient Greek philosophers, but it has proven to be a rather difficult task to come up with definitions for the various lexical word classes that have cross-linguistic validity”
Velupillai (2012: 121): “Because of the difficulty of distinguishing it from cliticization, it is beyond the scope of this book to discuss pronoun incorporation.”
Degand et al. (2013: 2): “What makes it difficult to tell apart discourse markers from modal particles?”
Song (2018: 79): “the distinction between a language and a dialect is a notoriously difficult one to draw”
Norris (2019: 5): “There are examples of languages that fit very clearly into each of those categories [i.e. types of gender], but there are also borderline cases that are difficult to classify”
Kilian (2021: 30): It is “difficult to determine whether localizers are verbal predicators“.
It may be that some of these authors actually mean that the difficulty lies in obtaining complete information – but this is not what they say. They all talk about the difficulty of drawing distinctions, and the purpose of this blogpost is to point out that drawing distinctions is not difficult. Of course, one needs to know what the distinctions are – but if one talks about a conceptual contrast in a scientific context, one can be expected to know what the contrast is.
So what is the problem here? I suspect that it is that the authors are not sure that they know what the distinctions really are (as comparative concepts). Bickel & Nichols seem to be unsure what the distinction between tense and aspect is; Dryer seems to be unclear about the precise difference between affixes and clitics; and Degand et al. may not be certain about how to distinguish between discourse markers and modal particles.
We often take our terms from the earlier literature, which provides salient examples but no clear definitions of many technical terms (maybe because it assumes that the concepts are innate and thus their definition is a matter of research, not of convention). Thus, when we take our terms “off the shelf” (i.e. the earlier tradition of linguistics), we may not have good characterizations of what they mean. For example, there simply is no clear delimitation of “affix” (from other bound forms) in the earlier literature (though I made a concrete proposal quite recently in Haspelmath 2021).
Once this uncertainty in the legacy literature is recognized, there is an easy solution, in principle – comparative grammarians (“typologists”) can define the concepts they use themselves, without (necessary) reference to the earlier tradition. If they create their own distinctions, they no longer have any reason to be unsure about the nature of the distinctions. And if they know exactly what their comparative concepts mean, they can apply them without difficulty to the languages they compare (as long as there is no missing data problem).
Consider the example of polar question marking that is studied by Dryer (2005). He says that
“The distinction between separate question particles and interrogative affixes is not always clear. It is common in verb-final languages for question particles to immediately follow the verb, and they often loosely attach to the verb as clitics. Because it is difficult to distinguish verbal suffixes from clitics that can only attach to the verb, these are not distinguished here”
Dryer does not say what exactly he means by “affix”, “clitic” and “particle” here. But in his chapter on definite articles, he says that definite markers which can occur on nouns or adnominal modifiers are regarded as clitics. Thus, for example, the Basque definite article -a occurs after the last element of a nominal, which may be the noun (e.g. etxe-a ‘the house’) or an adjective (e.g. etxe gorri-a ‘the red house’). Thus, the decisive criterion is not the spelling or any kind of “phonological cohesion”, but the promiscuity: Definite markers can occur on roots of different root classes (I adopted this criterion in Haspelmath 2021). (There was some discussion of this back in 2008 on the WALS blog.)
Using this definition, it would not be “difficult to distinguish verbal suffixes from clitics” – one just needs to determine whether the marker in question can occur on verbs only or also on adjectives or nouns. In an analogous fashion, Bickel & Nichols could specify what they mean by “tense” and by “aspect”, and then apply their definition to their data; and likewise for “inflectional copula” (Curnow), “case” (Iggesen), “modal particles” (Degand et al.), and so on.
(Maybe Dryer actually means that it is difficult to know whether a marker can occur on other elements, because grammars often give just one or two examples with a question marker occurring on a verb and do not say whether the element also occurs elsewhere. Then this would be the data incompleteness problem, which is indeed a difficulty of typology, as I noted earlier.)
Apart from the data problem, there is a terminology difficulty: We generally expect our terms to be self-explanatory, and we expect our colleagues to use familiar terms. Reading long sections of definitions is tedious, and even data appendixes (which have no space limitations) rarely contain fully explicit definitions. However, this expectation is often too optimistic – our terms are not always self-explanatory. What is “noun incorporation”? What is an “impersonal construction”? What is a “converb”? What is a “serial verb construction”? We typically agree on core cases, but where are the boundaries? Is it better to propose new terms for one’s comparative concepts, or should one propose new meanings for old terms? Either way, our decisions may make our readers unhappy.
So the data difficulty and the terminology difficulty are very real, and not easy to overcome.
But there is no classification difficulty: Once a comparative concept is defined clearly in such a way that its defining criteria are applicable uniformly to all languages, the classification is straightforward if we know the facts of the language.
Bickel, Balthasar & Nichols, Johanna. 2005. Inflectional synthesis of the verb. In Martin Haspelmath, David Gil & Bernard Comrie, Matthew S. Dryer (ed.), The world atlas of language structures. Oxford: Oxford University Press. (https://wals.info/chapter/22)
Curnow, Timothy Jowan. 2000. Towards a cross-linguistic typology of copula constructions. In Henderson, John (ed.), Proceedings of the 1999 Conference of the Australian Linguistic Society, 1–9. (http://www.als.asn.au)
Degand, Liesbeth & Cornillie, Bert & Pietrandrea, Paola. 2013. Discourse markers and modal particles: Categorization and description. Amsterdam: Benjamins.
Dryer, Matthew S. 2005. Polar questions. In Haspelmath, Martin & Dryer, Matthew S. & Gil, David & Comrie, Bernard (eds.), The world atlas of language structures, 470–473. Oxford: Oxford University Press. (https://wals.info/chapter/116)
Haspelmath, Martin. 2021. Bound forms, welded forms, and affixes: Basic concepts for morphological comparison. Voprosy Jazykoznanija 2021(1). 7–28. (doi:10.31857/0373-658X.2021.1.7-28)
Iggesen, Oliver A. 2005. Number of cases. In Haspelmath, Martin & Dryer, Matthew S. & Gil, David & Comrie, Bernard (eds.), The world atlas of language structures, 202–205. Oxford: Oxford University Press. (http://wals.info/chapter/49)
Killian, Don. 2021. Towards a typology of predicative demonstratives. Linguistic Typology (doi:10.1515/lingty-2021-2078)
Norris, Mark. 2019. A typological perspective on nominal concord. Proceedings of the Linguistic Society of America 4(1). 12-1–15. (doi:10.3765/plsa.v4i1.4515)
Rijkhoff, Jan. 2007. Word classes. Language and Linguistics Compass 1/6: 709-726.
Song, Jae Jung. 2018. Linguistic typology. Oxford: Oxford University Press.
Velupillai, Viveka. 2012. An introduction to linguistic typology. Amsterdam: Benjamins.