Regarding the area of “Speech, utterance, verbal expression.”, the OED says that the word has this primary sense: “
1. collect. pl. Things said, or something said; speech, talk, discourse, utterance; esp. with possessive, what the person mentioned says or said; (one’s) form of expression or language.
Often in such phrases as in these, other, etc. words, in (such-and-such) language; many words, few words (see also (def#22), (def#26)); to give words to, to put into words, to express by means of language; beyond words, incapable of being expressed in language, unutterable, unspeakable.”
So words are anything that’s expressed using language. As you might imagine, the full entry is longer than most religious tracts handed out by the most studious of proselytizers. Another interesting and applicable, and noteworthy, sense is sense 2:
2a. sing. Something said (= sense (def#1)); a speech or utterance; esp. defined by a possessive or demonstrative. arch.
2b. with negative expressed or implied, or with every: Any or the least utterance, statement, or fragment of speech; anything at all (said or written).
Those are the first few parts of the first two senses. There are 29 distinct (or reasonably distinct) primary senses given for word in the OED, including almost uncountably many compounds.