This character is a Other Symbol and is commonly used, that is, in no specific script. The character is also known as comic book conversation bubble.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. U+1F4AC offers a line break opportunity at its position, except in some numeric contexts.
The CLDR project calls this character “speech balloon” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: balloon, bubble, comic, dialog, message, sms, speech, talk, text, typing.
This character is designated as an emoji. It will be rendered as colorful emoji on conforming platforms. To reduce it to a monochrome character, you can combine it with Variation Selector-15: 💬︎ See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
Speech balloons (also speech bubbles, dialogue balloons, or word balloons) are a graphic convention used most commonly in comic books, comics, and cartoons to allow words (and much less often, pictures) to be understood as representing a character's speech or thoughts. A formal distinction is often made between the balloon that indicates speech and the one that indicates thoughts; the balloon that conveys thoughts is often referred to as a thought bubble or conversation cloud.