The runic alphabet is also called Futhark. That name comes from the first six sounds: f, u, th, a, r, and k. If you think that’s strange, may I remind you of where the word alphabet gets its shape from: Alpha, and Beta. The first two letters. Oh, simpler times.
Every rune has a phonetic sound, but according to the early users, also a connection to Norse mythology.
Now, why is that interesting when getting a tattoo? Because of the double meaning, and the versatility of the letters. Nobody can read runes nowadays, which allows you to create tattoos that barely anyone understands but yourself.