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It's been years since I read it. So I'm not sure when the book was published but I read it sometime before 2006. It was a single novel. Not a series.
I remember that the protagonists - humans are travelling in space, encounter this planet with aliens. They slowly work with the aliens to learn the language and teach them human language.
The aliens finally let the humans come down to the planet. Towards the end of the book they realise these aliens can't have kids, they eat their young? They live very very short lives? This ties into the starting of the book since among the first set of aliens who made first contact there was one who died? Almost dying? And they switched her for someone else in order to keep up the pretext.
Ok another thing I remember is that the aliens think very differently from humans. While humans think abstractly and create modular components to build a complex system. The aliens create spaceships where parts play more than one role, if you destroy part of it, other parts take up that role.
They had cool weapons, romance I think? I read the book in India, but it's an English novel.