כל vs בכל vs מדי
So I want to say "He writes to his friend in Israel every week" but I am confused how to say the "every week" part of the sentence. I have found 3 options and I don't know which one is the correct one because I don't know the difference between the words or how/when to use them. 1. הוא כותב לחברו בישראל מדי שבוע 2. הוא כותב לחברו בישראל בכל שבוע 3. הוא כותב לחברו בישראל כל שבוע
If someone (who actually knowns about correct Hebrew grammar) could tell me which is the correct sentence (with explanation) and how to use each of these words in a grammatically correct way that would help me understand.
The most correct is "מדי שבוע", but it's not commonly used in speech. The other two are equally correct to use in spoken language, although my intuition (as a native speaker) is to say "כל שבוע" and not ""בכל שבוע.
It would mean in every week. Adding ב to the start of a word is essentially equal to adding 'in' before a word. While it's correct, it's not widely used.
Apologies for the way those sentences came out... combine number 1 and 3 and separate the two sentences in number 2