Translation:All my friends have seen me with her.
"all my friends have seen me with hair" should be correct as well? It actually makes sense lol.
Not a silly question. It's because it's one of a class of verbs called 'strong verbs' which have irregular past tense forms. It's a Germanic grammatical feature. Most of the English irregular verbs (like freeze-froze-frozen) are a remnant of this feature from Old English. Why called 'strong verbs' you say (as opposed to weak verbs like 'duwen')? It simply refers to the fact that the stem vowel is changed in the verb's past tense instead of the end of the word (zag/zagen instead of zide/ziden) . The ending in the participle form of the verb also doesn't change. There are plenty of other strong verbs in Dutch - like 'slapen' (past tense: sliep/sliepen, past participle: geslapen).
Is it not also possible to translate it as "Already my friends have seen me with her?"
It says "al mijn vrienden" --> "all my friends".
Your sentence would translate to: "Mijn vrienden hebben mij al met haar gezien."
You can put a temporal adverb at the start of the sentence, but that will generally result in an inversion of the subject and the verb. E.g.:
- Ik ga vandaag naar school - I go to school today
- Vandaag ga ik naar school - Today I go to school
And an example with "al":
- De winkel was al een jaar dicht - The shop was already closed for a year.
- Al een jaar was de winkel dicht - Already for a year the shop was closed.
Because that would require a different position of al
Mijn vrienden hebben mij al met haar gezien.