Learn Turkish: Asırlarca bu topraklarda milletçe huzur içinde yaşadık. - We lived peacefully in these lands as a nation for centuries.

In asırlarca, the -ca suffix acts as an adverbial of extensive quantity. While asırlar just means "centuries", adding -ca translates to "for centuries" or "for many centuries." It emphasizes a vast, continuous stretch of time.

Why does the sentence use milletçe instead of bir millet olarak (as a nation)?

The -çe suffix here creates an adverb of collective entity. While bir millet olarak simply means "in the role/capacity of a nation," milletçe strongly emphasizes unity and togetherness, meaning "all together as a whole nation."

Why is toprak (land/soil) pluralized as topraklarda in this context?

In Turkish, topraklar is frequently used in the plural when referring to a broad geographic territory, homeland, or domain. If you used the singular bu toprakta, it would sound more like you were talking about a specific patch of literal dirt or soil on the ground.

Why say huzur içinde (inside peace) instead of the adverb huzurla (with peace)?

Both are grammatically correct and mean "peacefully." However, huzur içinde (literally "inside peace") is a very strong, natural collocation in Turkish for living or resting. It gives a vivid sense of being completely surrounded by or immersed in a state of peace.