The example you give is partially in English and partially in what I undestand is Gaelic: I couldn't tell you if the refrain has words in it or not: the song Nil Na La is a traditional song, meaning "Daybreak has not yet come". https://brendannolan.com/lyrics/nilnala.html

• Scat is the term used for jazz non-word singing Wikipedia
• Lilting is for Gaelic non-word singing Wikipedia

The example you give is partially in English and partially in what I undestand is Gaelic: I couldn't tell you if the refrain has words in it or not: the song Nil 'Na Lá is a traditional song, whose title means "Daybreak has not yet come". https://brendannolan.com/lyrics/nilnala.html

• Scat is the term used for jazz non-word singing Wikipedia
• Lilting is for Gaelic non-word singing Wikipedia
• Yodelling is the Alpine form of non-word singing Wikipedia

Wikipedia lists many other forms at Non-lexical vocables.