거울아 for "Mirror!". In some languages, the direct address forms of names have a suffix so they're distinguished from normal references. All CJK languages have this, so that you don't use the name by itself when addressing them directly. For example, if someone named 김영철 is an adult, we would use some title like 씨, 선생님, a ob title, and such. When there's no title at all, as is the case with children, you tag on 아 or 야 after the name. So if 김영철 is a small boy, you call him by 영철아, and never by 영철 alone (that will sound weird). If the name ends with no 받침, as in 영수, then you put 야 at the end, like 영수야. This applies to objects too when you address them like people, as you would in fairy tales. So for mirror, it is 거울아. Rain would be addressed with 비야, wind 바람아, the sun 해야, the moon, 달아, etc. This suffix works very well for this kind of usages. In English, you might have a hard time making "(Hey) Wind(,) blow for me" sound natural. In Korean 바람아 불어다오" is as natural as talking to your friend, and never confusing, because of this 아 suffix. As for -려무나, it is one of the imperative sentence endings. It has a very soft and endearing feel. Meaning-wise it's no different from 말해 줘, but sounds much warmer and inviting. -렴, which is it's shortened form, is used more widely in conversation: 가려무나, 먹으려무나, 말하렴, 해보렴, etc.