Recommendation
If you need the exact same brand voice across English and Spanish ads, create one custom voice with bilingual training and use language-specific prompt templates plus light human post-editing. Train on clean, parallel-style recordings (same speaker, matched delivery) and use prompt-level controls (tone, pacing, emphasis markers, pronunciation hints) to keep consistent cadence and natural pacing.

Why this works
A single bilingual voice preserves timbre and baseline prosody across languages. Parallel training (matching scripts in both languages) reduces drift. Prompt engineering then handles language-specific prosody and pronunciation (regional accent choices, emphasis patterns) so ads feel native without changing the brand personality.

Decision criteria (choose based on budget/quality/skill)
- Budget: Full custom voice cloning is costlier but gives best consistency. If budget is low, use a high-quality stock voice for one language and fine-tune only the other.
- Skill level: If you have audio engineering/localization expertise, produce your own studio samples for cloning. If not, record with a professional voice actor who can deliver matched takes.
- Team size/workflow: Large localization teams benefit from a single clone + style guide. Smaller teams may prefer separate localized voices and stricter prompt templates.
- Output quality: For broadcast/OOH use the trained voice + human phonetic edits. For social ads, prompt controls and minor retakes are often enough.

Practical checklist for ElevenLabs cloning & prompts
1) Recording set: 30–120 minutes of dry, noise-free speech per speaker. Use the same mic and chain for both English and Spanish takes. If you can only do less, prioritize 30+ minutes with high variety (intonation, question, exclamation, short/long sentences).
2) Parallel scripts: Prepare matched scripts in both languages with identical intent, sentence length and emotional beats. This helps the model learn equivalent prosody.
3) Accent decision: Choose a single regional target (e.g., neutral Latin American Spanish) and record or post-process to that target. Don’t mix accents in the same clone.
4) Metadata & labels: Tag samples with style (warm/confident), target language, and pacing (words-per-minute examples). Include a few “baseline” utterances you’ll reuse in tests.
5) Prompt template (use for each generation):
- Preface: “Voice profile: warm, friendly, authoritative. Target pace: 150 wpm. Breaths: minimal but natural. Emphasize product benefit phrases in bold.”
- Language marker: “[ENGLISH]” or “[ESPAÑOL - neutral Latin American]”
- Phonetic hints: add short bracketed hints for tricky names: John Doe [JOHN: jahn], or Spanish names [José: ho-SEH].
6) Prosody and pacing controls: Use ElevenLabs’ SSML/voice parameters or built-in sliders to set pauses (300–500 ms for sentence breaks) and adjust pitch/emphasis. If available, inject custom pause tokens where natural breath or emphasis is needed.
7) QA: Listen for incorrect vowel/consonant realizations in Spanish. Add targeted phonetic training samples or do per-utterance phoneme overrides.
8) Human-in-the-loop: For high-value ads, have a native Spanish speaker review and request minor phonetic corrections or re-record short samples.

Best-for / Avoid-if
- Best for: brands needing identical vocal identity across languages, high-volume campaigns, and teams able to record quality samples.
- Avoid if: you need many regional variants quickly or can’t supply consistent bilingual recordings — use localized stock voices instead.

Tools that help
Use ElevenLabs for cloning and generation; use ChatGPT to produce parallel ad scripts, phonetic hint lists, and concise style guides you can paste into prompts.

Quick final tip: Always keep a short canonical “brand soundboard” (10–20 canonical lines) in both languages to A/B after any change — it’s the fastest way to detect drift in tone or pacing.

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