Songs of the Sabbath Sacrifice is the principal source for angelic tongues at Qumran.
[1][2][3][4] The pseudepigraphical Testament of Job (c. 100 BCE–100CE) contains a conclusion which is believed to relate to the compiling of the hymnbook used by a Therapeutae community.
There is parallel description of sung prophecy among the Therapeutae in Alexandria by Philo, but no mention there of angelic tongues.
If a distinction is intended then 1 Corinthians 14:10 "There are doubtless many different languages in the world, and none is without meaning" may imply that "tongues of men" were intelligible, whereas 1 Corinthians 14:2 For one who speaks in a tongue speaks not to men but to God; for no one understands him, but he utters mysteries in the Spirit."
The problem with this is that the "angelic" tongues documented at Qumran and among the Therapeutae appear to be inspired, but coherent and intelligible, sung praise.