How I localized AI-generated emails for international markets without losing the human touch

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Earlier this year, I was handed an AI-generated content project with a deceptively simple goal: adapt email messages for international audiences.

This wasn’t my first time navigating global nuance. With an MBA in International Business and experience working on a global consulting project in Portugal, I’d already seen how messages land differently depending on culture, tone, and language. But this was my first time applying that lens to AI content generation in my MarTech AI role at HubSpot — and it was more complex than expected.

We already had an AI-generated email prompt that worked well in English—conversational, friendly, and context-aware. The challenge? Making it work in Spanish and French without sounding robotic, clumsy, or culturally off-base.

Sounds easy. It wasn’t.

The Hidden Complexity of “Just Localizing”

What we were really doing was asking an AI model — trained predominantly in English — to speak other languages as naturally as a native marketer would.

Our first attempts fell flat.

Example (original AI output in Spanish):

Here’s what we aimed for in English:

“I saw you were scoping around the platform and that you were interested in speaking with us. Would you like to meet on one of the following days?”

This is the original output in Spanish:

“Estuve revisando tus interacciones en nuestra plataforma y quería ofrecerme como tu punto de contacto.”

In English, it translates to:

“I reviewed your activity and wanted to become your point of contact.”

While grammatically correct, this sounded invasive in Spanish — like we were watching the user too closely. It didn’t feel natural. One reviewer called it “creepy.”

Here’s another example:

Original English intent: “I noticed you’ve been exploring our platform and expressed interest in connecting with us.”
Original Spanish output: “Me pareció interesante tu interés en nuestros servicios.”
Translation in English: “I found your interest in our services interesting.”

Again, it’s technically accurate, but it’s redundant and robotic. It’s the kind of phrasing that makes a reader stop and go, “Did a bot write this?”

The takeaway: Even when the translation is accurate, the tone can be off. And tone is everything in marketing.

The Shift from Translation to Language-aware Prompt Design

At this point, I realized we needed more than AI outputs — we needed a system for guiding the AI to think like a multilingual marketer.

I built a language-portable prompt framework — a structured prompt that could adapt across languages while respecting each one’s unique grammar, tone, and cultural context.