Languages and Linguistics

If you're a typological linguist, a language will have a particular structure related to the order of a subject, object and verb in a sentence, or the way certain sounds are produced. A language might be considered analytic (that is, the sense of a sentence is determined mostly by word order and the use of prepositions) or synthetic (the meaning is determined by the way the words in the sentence are modified - conjugation of verbs and declension of nouns). German variants tend to differ mostly with respect to pronunciation and local nomenclature but their essential structure, particularly as to word order (sticking the verb at the end of a sentence, for example) is basically the same, so I think most linguists would call them dialects. Yiddish is probably at the far edge of a German dialect and is often classified as a separate language although it is structurally mostly German.