The World English Bible, The NwT, The Int. Standard Bible, but then I’ve not researched ALL translations.
Robertson’s Word Pictures in the New Testament comments:
“Acts 22:9
But they heard not the voice (thn de fwnhn ouk hkousan). The accusative here may be used rather than the genitive as in verse Acts 22:7 to indicate that those with Paul did not understand what they heard (Acts 9:7) just as they beheld the light (Acts 22:9), but did not see Jesus (Acts 9:7). The difference in cases allows this distinction, though it is not always observed as just noticed about Acts 22:14; Acts 26:14. The verb akouw is used in the sense of understand (Mark 4:33; 1 Corinthians 14:2). It is one of the evidences of the genuineness of this report of Paul’s speech that Luke did not try to smooth out apparent discrepancies in details between the words of Paul and his own record already in ch. 9. The Textus Receptus adds in this verse: “And they became afraid” (kai emfoboi egenonto). Clearly not genuine.
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The Church spoke the language of the Gospels and the New Testament and understood it it to mean "heard". You also fail to give me a single example where the term "hear" is translated as "understand" anywhere else. It is somewhat pretentious of scholars today to presume they understand the koine Greek better than the Church did in her own language.
I disagree. The verb "heard" is used as is "made aware of," as in "I never heard of such a thing." Comprehension is not implied.
Matthew 13:13 proves him wrong.