Translation

The Signal bot provides three translation modes for cross-language communication in community groups.

On-Demand Translation (`!translate`)

Translate text or quoted messages on the fly.

Commands:

!translate <language> <text>: Translate text to a language.
!tr <language>: Reply to a message to translate it.
!tr <text>: Translate to English (default).
!trans: Alias for !translate.

Examples:

!translate spanish Hello, how are you?
!tr ja Good morning
!tr es                          (reply to a message)
!tr Bonjour tout le monde       (translates to English)

Languages supported: Over 50 languages including: en, es, fr, de, ja, ko, zh, ar, ru, pt, it, hi, uk, pl, tr, vi, th, nl, sv, and more.

Accepts ISO 639-1 codes (es, ja), full names (spanish, japanese), or common aliases (mandarin -> zh, farsi -> fa).

Rate limit: 10 translations per hour per user.

Requires: AI features enabled in the room (!room ai on).

Room Auto-Translate (`!room translate`)

Automatically translate all non-target-language messages in a room. When enabled, any message not in the configured language gets a translation posted below it.

Commands (Admin only):

!room translate on <language>: Enable auto-translate to the target language.
!room translate off: Disable auto-translate.
!room: Shows current translate status alongside other room settings.

Examples:

!room translate on english      Auto-translate everything to English
!room translate on es           Auto-translate everything to Spanish
!room translate off             Disable

How it works:

Bot detects the language of each message
If it differs from the room’s target language, the message is translated
Translation appears as: 🌐 Spanish -> English: [translated text]

Skipped messages:

Commands (starting with !)
Short messages (< 5 characters)
Emoji-only messages
Messages already translated (starting with 🌐)
Bot’s own messages

Rate limit: 30 auto-translations per minute per room.

Babel Fish Relay (`!trelay`)

Create a private relay room with bidirectional translation between two groups. The bot translates ALL messages flowing both directions — like a real-time Babel Fish.

Aliases: !trelay, !request_t, !reqt

How It Works

┌──────────────────────┐       ┌─────────────┐       ┌──────────────────────┐
│  Relay Room          │       │    Bot       │       │  Target Group        │
│  (Users + Bot)       │       │  (Babel Fish │       │  (Community)         │
│                      │       │   Translator)│       │                      │
│  User types in       │──────>│  Translate   │──────>│  "Juan [es]:         │
│  Spanish             │       │  ES -> EN    │       │   Hello everyone!"   │
│                      │       │              │       │                      │
│  "🐟 Sarah:          │<──────│  Translate   │<──────│  Sarah types         │
│   ¡Hola Juan!"       │       │  EN -> ES    │       │  in English          │
└──────────────────────┘       └─────────────┘       └──────────────────────┘

ALL messages from the target group are relayed back to the relay room (not just replies). This is true Babel Fish mode — full bidirectional translation.

Creating a Relay

Self-relay (create for yourself, single language):

!trelay <my_language> <room#/name>
!trelay spanish 5                     (you speak Spanish, group is English by default)
!trelay arabic tech                   (you speak Arabic, target "tech" group)

Two-language form (specify both languages):

!trelay <my_language> <group_language> <room#/name>
!trelay english spanish 5             (you speak English, group speaks Spanish)
!trelay french arabic tech            (you speak French, group speaks Arabic)

Multi-user relay (add others to the relay room):

!trelay english spanish 5 @user1 @user2 @user3
!trelay spanish tech @Maria @Ahmed

Anonymous relay (group names instead of display names):

!trelay --anon spanish 5
!trelay --anon english spanish tech @user1 @user2

Options

Flag	Description
`--anon` / `--annon` / `-a`	Anonymous mode: hides display names in both directions. Target group sees “Relay”, relay room sees the target group’s name instead of individual names.
`--named` / `-n`	Named mode (default): display names shown in both directions.

Room Selector

Use a group number from !groups (e.g., 5) or a keyword to search group names (e.g., tech). Must be at least 3 characters for keyword search.

What Happens

Bot creates a private Signal group with the bot + all specified users
Bot sends a bilingual welcome message in the relay room
Bot announces in the target group: 🐟 Babel Fish activated! [users] connected ([language] <-> [language]).
Relay -> Group: Messages typed in the relay room are translated and posted to the target group as Name [xx]: translated text
Group -> Relay: ALL messages in the target group are translated and posted to the relay room as Name: translated text

Anonymous Mode

In anonymous mode (--anon):

Relay -> Group: Messages appear as Relay [xx]: translated text (no display names)
Group -> Relay: Messages appear as GroupName: translated text (group name instead of individual names)

This is useful when you want to protect the identity of relay participants.

Managing Relays

Any user:

!relay end: End the relay for the current room (run in the relay room)

Admin only:

!relay status: List all active translation relays
!relay end @user: End a specific user’s relay

Examples

# Self-relay (you speak Spanish, group speaks English by default)
!trelay spanish 5

# Two-language relay (you speak English, group #5 speaks Spanish)
!trelay english spanish 5

# Multi-user relay (you + Maria + Ahmed speak French, group speaks Arabic)
!trelay french arabic tech @Maria @Ahmed

# Anonymous multi-user relay
!trelay --anon spanish 3 @user1 @user2

# Check active relays (admin)
!relay status

# End a relay (in the relay room)
!relay end

# End someone's relay (admin)
!relay end @Maria

Database

Translation features use two database additions (migration 036_translation_features.sql):

signal_groups table additions:

Column	Type	Description
`translate_enabled`	BOOLEAN	Whether auto-translate is on for this room
`translate_target_language`	VARCHAR(10)	ISO 639-1 target language code

translation_relays table:

Column	Type	Description
`id`	SERIAL	Primary key
`user_uuid`	VARCHAR(255)	UUID of the relay user
`user_name`	VARCHAR(255)	Display name of the relay user
`user_language`	VARCHAR(10)	Language the user speaks
`relay_group_id`	VARCHAR(255)	Signal group ID of the private relay room
`target_group_id`	VARCHAR(255)	Signal group ID of the community group
`target_language`	VARCHAR(10)	Language of the target group (default: `en`)
`anonymous`	BOOLEAN	Whether the user’s name is hidden
`status`	VARCHAR(50)	`active` or `ended`
`message_count`	INTEGER	Messages translated through this relay
`created_at`	TIMESTAMPTZ	When the relay was created
`ended_at`	TIMESTAMPTZ	When the relay was ended

Technical Notes

Translation uses OpenAI gpt-4o-mini with Local AI fallback
Language detection is done before translation to avoid unnecessary API calls
Relay messages use the format Name [xx]: text where xx is the language code
Auto-translate and relay both skip the bot’s own messages to prevent loops
Babel Fish relay forwards ALL target group messages (not just quoted replies)
Loop prevention: bot messages, relay-format messages, and commands (!) are skipped
Stale relays can be cleaned up after 24 hours of inactivity

For developer documentation including architecture diagrams, code paths, and integration details, see docs/TRANSLATION-SYSTEM.md.