You were raised in the mountain halls of the dwarves, either in one of their smaller settlements or one of the few remaining large dwarfholds that dot the mountain ranges of the world. As such, you likely hold to their system of beliefs and values, that honor is attributed both personally and to a family, that citizens all do their part to enrich their societies, and a sense of pride in your ancestors. The chief god of the dwarves, Moradin likely dominated your religious studies, if you had any. Military service is also mandatory in dwarvish society, and you have received full combat training as a result, regardless of eventual chosen occupation.
Choosing this background confers the following:
Dwarven Combat Training. You have proficiency with the battleaxe, handaxe, throwing hammer, and warhammer.
Dwarven Armor Training. You have proficiency with light and medium armor.
Languages. You can speak, read, and write in Common and in Dwarvish. Dwarvish is a language of hard consonants and guttural vowels, and that style of speech can and does bleed over into whatever other languages a native Dwarvish speaker learns.