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General Linguistics Thread

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1 Caliph_Lambda
I saw a lot of linguistics enthusiasts down in the intro thread, so let's talk about it right here. It's probably the interest I've maintained the longest in my life, both linguistics and languages.

My main interest lies in linguistic typology, morphosyntax and the construction of formal models informed by logic and mathematics towards explaining languages' properties, both convergences (e.g. ergativity from Basque to Sumerian, the universality of constituent structure and recursion, sorry Everett) and divergences (why is OSV so rare? Why are certain languages impossible?).

Recently an interest I've had is neural language models and their ramifications on linguistics, both as tools and as objects of linguistic study. They've made quite a splash, linguist Steven Piantadosi argues that the fact LLMs don't have any inherent grammar while producing syntactically impeccable text means universal grammar is bunk, while Chomsky fired back by saying that the amount of data used to get to that point is nowhere close to the amount needed for a human. LLMs are, after all, large and are fed text, while we have all kinds of other stimuli we take in within the first bit of our lives. Given LMs' growing importance I'm very excited for what will come next in linguistics; information theory is already proving to be an interesting tool to bridge the question of the functional pressures that may affect linguistic form, the Uniform Informational Density hypothesis is something to look into if you haven't yet.

It should also be said that LMs' real number vector-based semantic structure has predecessors in distributional semantics, a tradition in linguistics which goes back to the 50s, so it's not like linguistics is a stranger to the ways LLMs work. There's also some fun evidence about if LLMs have constituency structure, even ones trained on dependency treebanks, using probing studies. Info theory is proving some results here too, basically using mutual information to gauge how much about linguistic structure could be extracted from the embedding layers. So there's that continuity between discrete structure and continuous vectors.

I keep up with SCiL (Society for Computation in Linguistics) and a few of the SIGs of the Association for Computational Linguistics (SIGMOL which is about the mathematics of language, SIGARAB which is about Arabic, my native language, SIGPARSE about parsing, SIGMORPHON about morphology and phonology, and more). I also keep up with the BriGap workshops (Bridges and Gaps between Formal and Computational Linguistics), which try to unite the data scientist, empirically oriented NLP people with the theoretical linguists developing and formulating theories on human language. I think this will only grow and I'm honestly quite excited.
2 aryanpakichud
>>1

I read a short blog on Claude's tokenizer that I thought was worth sharing. It seems to standardize language between variants in training data (such as "space prefixed" and "non space" as mentioned), by wrapping word-like spans in begin/end markers and letting the end marker eat the following space. Those markers, plus a separate caps marker over the whole pretoken, remove the need for space-prefixed and capitalized variants of the same word (which amounts to factoring each surface form into a lowercase stem plus case and boundary features; "NASA" and "nasa" share a vocabulary entry).

Word markers presuppose whitespace-delimited words, so Han, Korean and emojis get none and go character by character. An orthographic word seems like the wrong unit for Arabic too (the article, prepositions and pronominal suffixes glue onto the host), and no concatenative segmenter can see a discontinuous root regardless. Does a scheme like this help or hurt for Arabic, relative to plain BPE?

Last edited 2026/08/11(Tue) 12:12:59

3 Caliph_Lambda
(all of this is to my knowledge, I recommend consulting other sources on this)
>>2
>An orthographic word seems like the wrong unit for Arabic too (the article, prepositions and pronominal suffixes glue onto the host)

Not necessarily true; according to Arnett and Bergen (2024) that hypothesized tokenizer alignment as one cause for lacking performance w/ morphologically complex languages, "no language is harder or easier for a language model to learn on the basis of its morphological typology. Differences in performance can be attributed to disparities in dataset size." This is ofc just one study, but still good to look into.
(Study here: https://arxiv.org/html/2411.14198v1)
>no concatenative segmenter can see a discontinuous root regardless

On this note actually, there's different solutions to this w/ classic GOFAI (multi-tape FSTs), but MADAMIRA which is (to my knowledge) the most popular Arabic morphological analyzer (I might even be able to do research with the people behind it next year; SQWEEEEEEEEEEEEEEEEEEEEE!) works by doing concatenative lexical lookups, only breaking the word down into the concatenative morphological parts. So "sa-a'kul" (I will eat) is broken down into (sa-), the future marker, and "a'kul", the 1st person present form of "to eat", but the past tense, using the same root "akal-" is parsed as a different word entirely. It's not going through the word and looking for the roots and stems, it just breaks it down concatenatively. So, for this, it's not a big problem.

Last edited 2026/08/11(Tue) 13:28:22

4 aryanpakichud
>>3 Sorry, busy few days.

>"no language is harder or easier for a language model to learn on the basis of its morphological typology"


Sure, but that conclusion doesn't cover Arabic. The paper says up front that it "focuses on two types of languages: fusional and agglutinative languages". MorphScore, the part that actually tests boundary alignment, is 22 languages, 11 of each, with no Semitic languages. Funny enough, their follow-up paper builds its gold segmentations from the longest shared sequence of wordform and lemma and keeps only what recomposes by concatenation, "in order to remove irregular forms and examples of non-concatenative morphology", concluding "Therefore, this approach only covers fusional and agglutinative languages" (kataba/kātib is their example). Arabic isn't in the resulting 70, though Hebrew is (in the appendix). Poelman, Bauwens & de Lhoneux (EMNLP 2025) re-run all three hypotheses and find each conclusion confounded, which is a better version of what I'm getting at.

>It's not going through the word and looking for the roots and stems, it just breaks it down concatenatively. So, for this, it's not a big problem.


The mechanism is as you describe, though I ended up reading it the other way. I installed CAMeL Tools (its calima-msa-r13 is based on almor-msa-r13, the database MADAMIRA ships with) and found that the lookup is concatenative, but the database lists 72,734 stems against 35,337 lemmas, so سآكل and perfective أكل both come back with lemma أَكَل. This relation is captured by enumeration, not by analysis. There are root and pattern fields too (سآكل gives root=#.ك.ل, pattern=سَآ2ُ3, where # is an underspecified weak radical), but those are CALIMA's addition rather than MADAMIRA's: Taji et al. (2018) say "roots and patterns are not part of the SAMA/ALMOR database that we base our work on", and nothing in the analysis reads them. Essentially, someone had to hand-write the roots (they don't fall out of the lookup), and a subword tokenizer has neither the stem list nor the annotation (BPE only emits contiguous substrings, so anything it learns has to be a straight run of the surface form).

SPLINTER is somewhat interesting, its Hebrew models gain on QA and segmentation and tie on parsing, but Arabic gets intrinsic evaluation only.

If you do end up with the MADAMIRA people (hope you do), I'd be curious whether anyone has tried root and pattern output as supervision for tokenizer training itself. MorphBPE keeps merges from crossing morpheme boundaries and is implemented in Fanar, but that's still concatenative supervision. I can't find anyone using the discontinuous root as the training signal.
5 Caliph_Lambda
>>4
> Sure, but that conclusion doesn't cover Arabic. The paper says up front that it "focuses on two types of languages: fusional and agglutinative languages". MorphScore, the part that actually tests boundary alignment, is 22 languages, 11 of each, with no Semitic languages. Funny enough, their follow-up paper builds its gold segmentations from the longest shared sequence of wordform and lemma and keeps only what recomposes by concatenation, "in order to remove irregular forms and examples of non-concatenative morphology", concluding "Therefore, this approach only covers fusional and agglutinative languages" (kataba/kātib is their example). Arabic isn't in the resulting 70, though Hebrew is (in the appendix). Poelman, Bauwens & de Lhoneux (EMNLP 2025) re-run all three hypotheses and find each conclusion confounded, which is a better version of what I'm getting at.

This I did not know about! And on that note, I think you're right. I think formal languages and automata could yield an interesting conclusion here given the question is about analyzing a string and what's kept in memory and what isn't. but I'm finding both conflicting information on the place of multi-tape FSTs on the Chomsky hierarchy (some have said they're mildly context-sensitive, others say they're snug at the regular level) as well as the generative capacity of subword tokenizers and if they match (they say they're regular, but I'm not fully sure). I should look into that. But from what I see (and I could be wrong), I think multi-tape FSTs exceed the capacity of subword tokenizers to analyze discontinuities in a string.

I've considered if Arabic root-and-pattern morphology is actually context-sensitive given the manner in which a string's features (i.e. the root and pattern) have discontinuous dependencies similar to ones in Swiss German syntax, but this is a surface-level similarity between the two, so I can't say for certain.
(UPDATE 28/9/2026: No, Arabic morphology is not; it remains regular because the discontinuous dependencies are not unbounded, unlike that of Swiss German. Moreover, given the fact that Arabic morphology does not have unbounded infixes, it isn't really even context-free.)
Compared to syntax it seems morphology is given the short end of the stick with formal analyses but that seems to be changing; Distributed Morphology feels like a step towards this with morphology considered an extension of syntax (rejecting strong lexicalism), but that's on the Minimalist side of things which is substantially less formal in the formal language theory sense. LrFG, Lexical-Realizational Functional Grammar is new by formalism standards, beginning in 2020, and there's still challenges to its formalization (Przepiórkowski 2025 mentions a couple).

>If you do end up with the MADAMIRA people (hope you do), I'd be curious whether anyone has tried root and pattern output as supervision for tokenizer training itself.

Thanks man! It's one of the things I'm interested in, i.e. linguistic structure and LLMs' ability to encode it.

Last edited 2026/09/27(Sun) 21:04:49

6 aryanpakichud
>>5

There's a survey of multi-tape automata with a section on asynchronous being more expressive than synchronous, which you might find useful, and Dolatian & Rawski (PWPL 26.1, 2020) have Arabic template-filling as strictly local over multiple tapes, so below full FST power rather than above it (which I wasn't expecting).
7 Caliph_Lambda
>>6
>Dolatian & Rawski (PWPL 26.1, 2020) have Arabic template-filling as strictly local over multiple tapes, so below full FST power rather than above it (which I wasn't expecting).

Oh this is VERY unexpected! Arabic morphology as subregular didn't make much sense until they showed the optimaility-theoretic morphophonological potential realizations of Arabic words as actually being quite simple given the constraints over combinations of consonants and vowels (showed with Optimality Theory). Given the subregularity it COULD mean that a tokenizer can see Arabic words fine but I don't know if this carries through all of Arabic morphology or just morphophonology.

Last edited 2026/08/16(Sun) 13:11:04

8 aryanpakichud
>>7
>optimaility-theoretic morphophonological potential realizations of Arabic words


I'm not sure what this means, please expand
9 Caliph_Lambda
>>8
> I'm not sure what this means, please expand

Optimality Theory is basically an approach to language (mostly phonology but LFG syntacticians have integrated some of those ideas there too) that thinks of linguistic form as a constraint satisfaction problem, where a word, or sentence, or string of phonemes at large are the optimal result given universal constraints. It doesn't seem to be used here as anything other than notation (not importing OT baggage) for what combinations of consonants and vowels are licit in Arabic.
It's far more complex than this, there's arguments for what phonological phenomena it accounts for and what it doesn't, stuff that I don't know too much about.

Last edited 2026/08/17(Mon) 08:37:13

10 aryanpakichud
>>9

I see, much appreciated.
11 Caliph_Lambda
>>2
Paging Pakichud, Paging Pakichud, Paging Pakichud!
Something new I found today that might answer your question: BPE does not seem to be sufficient for non-concatenative morphology, right as you said! There's a few tokenizer models that are meant to work for them, linking papers for them here.
There's SPLINTER:
https://arxiv.org/abs/2503.14433
MorphBPE:
https://arxiv.org/abs/2502.00894
Semitic Root Encoding (SRE):
https://aclanthology.org/2025.arabicnlp-main.3/
12 aryanpakichud
>>11

hmm. much appreciated kind sir, I'll read these over my coffee monster mango loco tomorrow morn

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