'They have began to...'

I begin (present) / I began (simple past) / I have begun (past participle), as sing / sang / sung or swim / swam / swum, still sound like 'proper' English to me. (These are one group in the remnants of 'strong' verbs in English and its predecessors, where the vowel changes in the stem.)

But I did hear the other day: 'operas sang in languages you can't understand'. OK, that was just something heard in the pub, but on the radio,  from an 'expert' : 'They have began to...' ?