LINE vs WhatsApp: register and tone differences in Thai hospitality
Thai-domestic guests overwhelmingly use LINE (56M MAU in Thailand). International inbound guests use WhatsApp (208% YoY growth in Thailand in 2024). The same hotel will respond on both channels; the appropriate tone differs.
LINE — Thai-domestic register
What it is. LINE is the SMS-replacement of Thailand. Thai guests use it constantly, throughout the day, in short bursts. The medium is closer to a chat with a friend than to a formal channel.
Tone implications:
- Messages are concise. A 3-paragraph reply on LINE feels excessive; the same content broken into 2-3 short messages reads more naturally.
- Stickers are normal in established conversations (not the first reply). A Thai LINE Official Account responding to a long-time guest can use a polite hotel-branded sticker as a closer. A first reply should remain text-only.
- Politeness particles still required. Casual register does not mean dropping ค่ะ/ครับ. Even 1-line LINE replies should end with the particle.
- Voice messages occur. The AI should not generate them, but if a guest sends a voice message, escalate to human (do not attempt transcription as the basis for an automated reply).
- Quick replies / rich menus — LINE Official Accounts support these; a hotel may surface common actions (Check rates, Contact reception, Restaurant menu) as buttons. The AI's text replies should mirror this brevity.
WhatsApp — international register (and Thai-formal)
What it is. WhatsApp is used by international guests inbound to Thailand, by some Thai guests for hotel communication (more formal than LINE), and by Thai-domestic guests in business contexts.
Tone implications:
- Messages are slightly more formal than LINE. A complete paragraph reply is normal and expected.
- No stickers in hotel-to-guest communication. WhatsApp supports them, but in hospitality the convention is text + occasional emoji at most.
- For Thai-language replies on WhatsApp, use a slightly more elevated register than LINE — fuller sentences, no abbreviations, fewer line breaks.
- For English replies, use standard hotel correspondence register — close to email tone but a notch lighter.
Choosing register on inbound
Read the guest's first message:
- Short, lower-case, abbreviated, possibly with emoji → guest has set a casual register. Match it (still polite, but lighter).
- Full sentences, formal greeting → match the formality.
- Mix of languages in one message → respond in their primary language (the one with most words), not by mirroring the mix.
Channel-specific formatting rules
| Aspect | LINE | |
|---|---|---|
| Reply length | 1-3 short messages | 1 longer message |
| Greeting | Single line OK | 2-line greeting + body OK |
| Bullet lists | Use for rates, hours | Use for rates, hours |
| Stickers/emoji | OK in ongoing thread, not first reply | Sparingly, never first reply |
| Closing | Brief (ขอบคุณค่ะ) | Fuller closing (offer to help further) |
Crossover: international guest contacting via LINE
Rare but happens (Korean and Japanese guests sometimes use LINE; Thai-resident expats use it). Default to WhatsApp register on the LINE channel — the guest is using LINE because it's their preferred channel from home (Korea, Japan), not because they want Thai-domestic casualness. Reply in English (or their language if known) with standard hospitality tone.