Puirt à beul (pronounced "poort-ah-buel") is a special type of singing that comes from Scotland and Ireland. It means "mouth music" in Gaelic.
Instead of singing actual words, puirt à beul singers use sounds, like "tiddley-iddley-aye" or "ho-ro-hi-ri-ri" or "hoo-lay-lay" to make music. The sounds are put together in a pattern that sounds like a song, even though there aren't any real words.
Puirt à beul was often used for dancing, and the music would match the beat of the feet on the floor. Some people still sing puirt à beul today, and it's a fun and lively way to make music without needing any instruments.