Anecdotal but wonder if it has import.... Was working with an Indian team, all w good English, but certain 'sounds' in English they always seemed to struggle with and often 'reverse'. Most common example (we were writing code for Geo-location stuff) was "Ohio" vs "Iowa" ....the 'Ai' vs 'oh' vs 'ah' sound gave several of them loads of difficulty.
One poor chap simply always reversed Iowa and Ohio....even worse when he was nervous or busy.
It just tweaked my memory and made me wonder about 'too-oh' vs 'oh-too' in a language not native to you...
Thanks for indulging a memory!