The word "toe toe" can be spelled in various ways, depending on the phonetic transcription used. In the International Phonetic Alphabet (IPA), the transcription of this word is /təʊ təʊ/. This means that the first syllable is pronounced with a short "o" sound (like in "not"), while the second syllable is pronounced with a schwa (like the "u" sound in "cup"). The repetition of the "o" sound in the two syllables is a feature of reduplication, a common academic term for a phenomenon where words or phrases are repeated to form new words or phrases.
The word "toe" can be traced back to Old English, where it was spelled "ta" or "tae". It stems from the Proto-Germanic word "tauwō" or "tauwaz", which meant "toe" or "finger". This same word can be found in other Germanic languages, such as Old Norse "tá", Old Frisian "to" or "tā", and Old High German "zēha" or "zēha". As for the repetition of the word "toe" in "toe toe", without any further context or information, it could be unique and unrelated to the etymology of the word "toe".