the comparison of sh and ch

[Mauro]

Turkish (and Hungarian too, IIUC) has a feature called "vowel harmony". 

And don't forget Eastern Lombard   , one of the few Romance languages with vowel harmony (with its own rules, ofc). It's triggered by adding suffixes which include a stressed -ì or -ù (which are very common: diminutive and accrescitive suffixes and verbal conjugations) and it raises the quality of all the preceding vowels, except [a]

kortèl = knife, kurtilì = small knife
möer = to move , muìt = moved
balòt = stone, balutù = boulder