"My friend helps me."
Translation:ידידה שלי עוזרת לי.
Hayadid is "the friend" and the English sentence doesn't have "the".
Yedidati/Yedidi are correct but very formal.
AFAIK In English it's not possible to specify both determination and possession as "my friend" implies both (I think you'd say "a friend of mine" to mean an unspecified one); in Hebrew it's possible though, so "ה" could (should?) be there. Am I correct?
@jimmy930731: No, any noun can have the definite article, the possessive, both or neither in Hebrew.
הלכתי לטיול עם הכלב שלי - I went walking with my dog - strongly implies that I have only one dog.
הלכתי לטיול עם כלב שלי - I went walking with my dog - does not imply that I have just one dog.
הלכתי לטיול עם חברה שלי - I went walking with a female friend of mine - may or may not be my girlfriend, although using the word instead of yedida implies it.
הלכתי לטיול עם החברה שלי - she's my girlfriend - no ambiguity about it.
Is it a special exception among the nouns? That ידיד שלי doesnt need a ה?
ok i donno why its like this and how you need to know when the "frieand" is a boy\girl in the Translation BUT ידיד=boy ידידה=girl boyfrieand=חבר girlfriend= חברה in israel, its dosent really matter too much if you say חברה/ידידה חבר/ידיד