'Sawadee kab' is the romanised form of สวัสดีครับ, the standard polite greeting used by male speakers in Thailand, roughly meaning hello. This particular clip appears to be a user recording from a Discord voice chat, captured with Microsoft Game DVR, rather than a line from a film or show. Short greeting clips like this circulate on soundboards because they work as instant, friendly openers, and Thai greetings are popular with travel vloggers, language learners and meme creators riffing on Thailand.