Charles Ellicott Commentary Luke 1:64

"And his mouth was opened immediately, and his tongue [loosed], and he spake, blessing God." — Luke 1:64 (ASV)

His tongue loosed.—The verb is supplied by the translators because the one previously used applied strictly only to the mouth.

He spake, and praised God.—Probably, in substance, if not in words, as in the hymn that follows. The insertion of the two verses that follow seems to imply that some interval of time passed before its actual utterance.