Formal:
* Mae fy ffrindiau yn… (This literally translates to "My friends are...")
Informal:
* Fy ffrindiau 'ma... (This literally translates to "My friends here...")
* Mae fy mhedwar ffrindiau yn… (This literally translates to "My four friends are...")
* Fy chymdeithasau... (This is a more informal way of saying "my friends" and literally translates to "my companions")
Example sentences:
* Mae fy ffrindiau yn dod i'r parti. (My friends are coming to the party.)
* Fy ffrindiau 'ma yn hoff o fwyd Indiaidd. (My friends here like Indian food.)
* Fy chymdeithasau yn fy nghartref. (My friends are at my house.)
Remember that the best way to say "my friends are" in Welsh depends on the context and the formality of the situation.