～てもいい (Verb)It's okay to, It's alright to, Can/may

The てもいい pattern expresses that something is acceptable or allowed. With verbs, it's used to give or ask for permission, such as 食べてもいい？ (Can I eat this?') It can also be used with nouns or adjectives to ask if a condition is acceptable, like 冷たくてもいい? ('Is it okay if it's cold?) when referring to a drink, for example.

Both Verb + てもいい and てもかまわない are used to give or ask for permission. The difference is tone and formality. てもいい is a basic, everyday expression, while てもかまわない is slightly more formal and often used in writing or professional contexts to mean 'It doesn't matter if…' or 'It's fine if…'

The Verb + て form is used to connect a verb to another verb, or another part of the sentence. When combined with もいい (meaning 'even' + 'good' or 'okay'), it asks for or grants permission. For example, 食べてもいい？with a question mark means 'Can I eat this?' (literally, 'Is it okay even if I eat this?'), while 食べてもいい with no question mark means 'you can eat it.'

The ても form has the core meaning of 'even if.' One common use is Verb + てもいい, which gives or asks for permission—for example, 食べてもいいですか？ literally means 'Is it okay even if I eat this?' but works like 'Can/May I eat this?' in English. Similarly, といってもいい means 'It's okay even if you say...' but is used to express 'You could say' or 'One might say.'

The ても form means 'even if.' One common use is Verb + てもいい, which gives or asks for permission (e.g. 食べてもいい？ = 'Can I eat this?') A related pattern is てよければ, which uses the conditional form of いい (よければ) to mean 'if it's okay.' It's often used to make polite offers, like 私でよければお手伝いします ('If I'm okay [as a choice], I'll help').

ても has the core meaning of 'even if.' One common use is in Verb + てもいい to ask or give permission. For example, 食べてもいいですか？ means 'Can/May I eat this?' (literally, 'Is it okay even if I eat this?') More broadly, ても can also express contrast. For example, 寒くても行きます means 'I'll go even if it's cold.'