Jo 38:7
When the morning stars sang together
And all the sons of God shouted for joy?
This passage and others apparently reveal a belief among some Jewish communities that angels sang. The natural corollary is that angels had a language, and that language would naturally be supposed to be a superior one.
Famously Paul at 1 Cor 13 refers to such angelic language. Many commentators have discussed this passage with a general denial that Paul was to be taken literally. Perhaps this is due to ignorance of the belief that not only do angels have a language, but humans could be inspired to use it.
The Qumran community apparently shared this belief. Fragments of a document extensively describe singing in the tongue of angels.
Songs of the Sabbath Sacrifice - Wikipedia
The next example is the Testament of Job (T of J) written by best estimate around 100 BCE.. The work is essentially a midrash style rewrite of the book of Job. It's praise of Job's piety focuses upon his selfless giving of himself and his riches and his patient willingness to suffer evil. The author and the community it came from are debated. Some say the Qumran community while others postulate the Therapeutae, an obscure sect in Alexandria. That group should be a topic for a thread in itself.
The T of J is a fascinating work, revealing a soteriology in some ways Christian-like in others unequivocally Jewish (such as the directive to not Gentiles). For the purpose of this thread I'll share a section that assumes angelic language AND it's human use under ecstatic hymn singing. As a set up to the following, Job pulls out magic girdles that God had previously given him, he gives them to his 3 daughters.
21 Now then, my children, in keeping these, you will not have the enemy plotting against you nor [evil] intentions in your mind because this is a charm (Phylacterion) from the Lord. 22 Rise then and gird these around you before I die in order that you may see the angels come at my parting so that you may see with wonder the powers of God.” 23 Then rose the one whose name was Day (Yemima) and girt herself; and immediately she departed her body, as her father had said, and she put on another heart, as if she never cared for earthly things. 24 And she sang angelic hymns in the voice of angels, and she chanted forth the angelic praise of God while dancing. 25 Then the other daughter, Kassia by name, put on the girdle, and her heart was transformed, so that she no longer wished for worldly things. 26 And her mouth assumed the dialect of the heavenly rulers (Archonts) and she sang the doxology of the work of the High Place and if anyone wishes to know the work of the heavens he may take an insight into the hymns of Kassia. 27 Then did the other daughter by the name of Amalthea’s Horn (Keren Happukh) gird herself and her mouth spoke in the language of those on high; for her heart was transformed, being lifted above the worldly things. 28 She spoke in the dialect of the Cherubim, singing the praise of the Ruler of the cosmic powers (virtues) and extolling their (His?) glory. 29 And he who desires to follow the vestiges of the “Glory of the Father” will find them written down in the Prayers of Amalthea’s Horn.
While some have found it too incredible that a Jewish work could include such a story and sought to dismiss it as work of Christian redaction, in fact there is no basis for that assumption. The rest of the work is overtly Jewish which would be surprising if a Christian had adapted the text. And the Qumran fragments suggest something similar was current.
In conclusion, there is good evidence that some Jewish communities included belief in angelic language as a charismatic means to sing praise to God. Judaism was truly diverse. There is much more that could be discussed.