Ngm is a common Brazilian Portuguese internet abbreviation for ninguém, and liga completes the dismissive phrase ninguém liga, meaning nobody cares. The wording comes from everyday online slang rather than a film, song, or television catchphrase, which is why it works so well as a standalone reaction. Short voice clips like this spread through meme pages, short-form videos, and group chats, where a quick spoken shrug is easier than typing a reply. Its lasting appeal is its bluntness, it says the quiet part out loud in under three seconds.