～てもいいIt is alright/fine/okay even if, Can/may, ~ is also okay

The two grammar points are used in different contexts, although they seem similar. The form "Verb + てもいい" is used to ask for or give permission to do something. For example, "ここで写真を撮ってもいいですか?" asks "Is it okay to take a photo here?" On the other hand, "てもいい" used alone doesn't ask or give permission, but instead implies something is permissible or acceptable. You might hear this in a broader context- for instance, a teacher might say "困ったことがあったら質問してもいい", meaning "If you have a problem, you're allowed to ask a question". Essentially, "てもいい" places less emphasis on a specific action, and more on the general idea of acceptable behaviors.

Both "てもいい" and "てもかまわない" essentially convey the meaning of "it's okay to do", but "てもかまわない" is a bit softer, gentler, and more polite than "てもいい". So, you might use "てもかまわない" when talking to someone elder or of higher status to show respect. On the other hand, "てもいい" is more casual and commonly used among friends or peers.

The Japanese grammar point "てもいい" is used when you want to give or ask for permission to do something, in essence, conveying the idea that it's okay or acceptable to do the action. On the other hand, "ても", without the "いい", is used to express the hypothetical condition "even if", suggesting a condition or situation that might occur, regardless of the result or consequence.