You age very slowly.

You are incredibly strong.

You are extremely lucky.

Your stealth is unparalleled.

Your Constitution Score increases by 1. You choose whether your Strength or Dexterity score increases by 1. Your Intelligence increases by 1. Your Wisdom increases by 2.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You have advantage on saving throws against poison, and you have resistance against poison damage (explained in the “Combat” section).

Dwarven Combat Training
You have proficiency with the battleaxe, handaxe, light hammer, and warhammer.

Tool Proficiency
You gain proficiency with the artisan’s tools of your choice: smith’s tools, brewer’s supplies, or mason’s tools.

Stonecunning
Whenever you make an Intelligence (History) check related to the origin of stonework, you are considered proficient in the History skill and add double your proficiency bonus to the check, instead of your normal proficiency bonus.

You've used your natural abilities well and honed skills to assist you in your daily life as a captive slave.

A dwarfling reaches adulthood at the age of 100 and generally lives to be 1000 years old. 

Most Dwaflings are lawful, with a strong moral compass for what they believe is right and fair. Whether they are stern like their Dwarven kin or more compassionate like their Halfling kin, is purely up to which has a stronger influence on their earlier year. Normally they adopt a balance between the two.

Dwarflings average 2-4 feet tall and weigh about 40-120 pounds. Your size is Small.

Your base walking speed is 25 feet.

When you roll a 1 on the d20 for an attack roll, ability check, or saving throw, you can reroll the die and must use the new roll.

You have advantage on saving throws against being frightened.

You can move through the space of any creature that is of a size larger than yours.

You can speak, read, and write Common, Dwarvish, and Halfling.

Dwarvish is full of hard consonants and guttural sounds, and those characteristics spill over into whatever other language a dwarf might speak.

The Halfling language isn’t secret, but halflings are loath to share it with others. They write very little, so they don’t have a rich body of literature. Their oral tradition, however, is very strong. Almost all halflings speak Common to converse with the people in whose lands they dwell or through which they are traveling.