The spelling of the word "the the" is actually incorrect as it is redundant. However, if we were to transcribe it phonetically, it would be pronounced as /ðə ðə/. The first "the" is pronounced with the voiced dental fricative sound /ð/ followed by the schwa vowel sound /ə/. The second "the" is also pronounced with the same sound and vowel. In English, the definite article "the" is used before a noun to indicate that the noun is one specific object.
The word "the" does not have an etymology as the word itself is a definite article in English, used to specify a noun as something already known or previously mentioned in context. However, "the the" is not a recognized word or phrase in English, so it does not have a specific etymology either. It may instead be a typographical or grammatical error.