I've previously asked Are questions about the languages themselves (without referencing a specific text) on topic?, but since asking it the list has been updated by me and other users with more examples (thanks David and Susan!). The current top-voted answer didn't have many of these examples to work from initially, and attempts to get the OP to update his response have been fruitless. According to our help page / site tour, questions about the Greek, Aramaic, and Hebrew languages are off topic. But this clearly requires some nuancing in practice.
In the process of adding more questions to the list, I've come to realize this is likely a more nuanced issue than a mere Boolean response can address (yes or no). The impetus for this meta post is this question: What are the various ways that “elohim” has been translated?, which I've currently placed on hold pending further community guidance.
I propose that we actually have multiple categories of questions and some different guidance must be given for each of them. As such, I've broken the list of questions into these categories for discussion's sake (it would be too tedious to list all of them in each answer). Ideally, answers will focus on which categories are on or off topic, and if any special caveats are needed for any of them. Feel free to also disagree with category divisions and to propose different ones.
Categories of Original Language Questions Without Specific Texts
Questions about learning the language
Questions about the meaning or translation of a specific word or phrase
Questions about the frequency or other statistical usage of a specific word, phrase, or linguistic feature
Questions challenging or seeking support for a claim about the language
Questions about a term or concept in a different language (including another biblical language) and how it relates to words in an original biblical language
Questions about the historical shift in meaning or usage of a specific word or phrase
As a caveat, I believe that vague collections (e.g. 'the Bible', 'Scripture', 'the New Testament', etc.) do not qualify as one specific text (largely because they contribute to questions that are too broad or unclear). However, other textual divisions may qualify depending on the question—discretion must be applied to each case (e.g. J/Yahwist source, pastoral epistles, Johannine corpus, etc.).