What word is valid across the largest number of different languages, and as different part-of-speech? (The precise term is interlingual homographs/heteronyms/polysemes)
'rate' is both verb, noun and adjective in English, so count that as 3. 'rate' is a loanword but also a (distinct) noun in German ('instalment'), in French: (noun) 'spleen' and also as verb (present tense of 'rater'), and again a loanword in Norwegian. Giving us a grand total of 3+2+2+1 = 8.
- I am not asking about homonyms within the same language (e.g. 'run' or 'set' have >400 meanings in English). I don't care about straight homonyms, for these purposes that all only boils down to 3 distinct meanings (noun, verb, adjective) for set.
- Ignore capitalization (e.g. for German nouns)
- Exclude universal loanwords like pizza (because it's the same word across languages, not a homograph.)
- Exclude proper nouns (unless they also have a separate meaning, e.g. 'scotch', 'go dutch'..).
- Include noun-, adjective- and verb-stemming
- Include accents as being significant, hence plies, pliés are both valid in English and French.
- Include colloquial usage, as long as it's common usage.
- Words must be 2+ letters (arbitrarily, to avoid the 'letter 'A' is the name for the letter A, in languages X,Y and Z' definition that Muke quoted. But allowing unusual definitions like wye or cym, as he cited.
(Motivation: this question arose (legitimately) from a SO question "Data structure for multi-language dictionary?"
On-topicness: If anyone quibbles whether this is a practical, answerable question based on actual problems that you face, see preceding Motivation remark; also I wanted to ask this on NLP/CL, but that's sadly closed, and non-English questions are offtopic for EL&U, and this is probably neither on-topic nor well-suited to the general StackOverflow audience. So yes, Computational Linguistics&NLP is on-topic for Linguistics.SE)