Formal:
* Euphonious: This word emphasizes the pleasing sound of the words themselves.
* Mellifluous: This word suggests a smooth, sweet, and flowing sound.
* Harmonious: This word implies a pleasing combination of sounds.
* Dulcet: This word describes a soft, sweet, and soothing sound.
Informal:
* Pleasant: This is a general term for something that is agreeable to the senses.
* Nice: This is another general term that can be used to describe something that is pleasing.
* Soothing: This word suggests that the sound is calming and relaxing.
* Charming: This word implies that the sound is attractive and captivating.
* Catchy: This word suggests that the sound is memorable and easily sticks in the mind.
The best word to use will depend on the specific context. For example, if you are describing a piece of music, you might use "euphonious" or "mellifluous." If you are describing someone's voice, you might use "dulcet" or "charming."