This argument has it backwards.
I was taught that prefixes should come from the same language as the root.
And, when you think about it, 'two-pedal' and 'bi-footed' sound pretty
Bi-gram sounds just as ridiculous to anyone who learned Greek and Latin
in school because it attaches a Latin prefix (bi- < Latin bis 'twice')
to a Greek root (-gram < Greek gramma 'letter'). Di-gram is preferred
since it uses the Greek prefix di- < Greek dis 'twice'.
For the same reason, tetragram (cf. Greek tetrakis 'four times') is to be
preferred to quadrigram, since quadri- is a Latin prefix.
Christophorus Baderus Grammaticus