Unlike the veinless, nerveless cartilage of the nose and ears, the tongue is a muscle with nerves that feel and veins that bleed. Luckily, protruding your tongue gives your piercing direct top and bottom access to the piercing site and clears it from any other bodily obstructions. This gives your piercer lots of space to work their magic and makes the entire process go by quickly. It also means that the barbell and both of its ends are fully visible, which makes threading the ends onto the jewelry a cinch.
Ask anyone with a tongue piercing and they'll probably all tell you that it didn't hurt as much as they thought it would. There will be significant swelling for the first 2-4 days, and the reality is to expect some discomfort, soreness, slurred speech, and fatigue.
You can do "ice rests" to alleviate pain during the first 24-48 hours. Set an ice cube on your tongue on and off as you can tolerate it, but don't suck or chew on the ice. Plan on a soft food diet those first few days or even the whole first week. Think straws and spoons: shakes, smoothies, purees, yogurt, applesauce, ice cream, etc.
Tongue piercings have a less robust cultural anthology than most other types of body adornment; however, it does have roots in Aztec and Mayan religions and transcendent applications among a few Northwestern Native American tribes. It is also part of a modern deity-offering sacrifice and predictor of good (or bad) fortune for villages in Nepal.
Historically speaking, tongue piercings were meant to be temporary. The permanent body piercing we all know and love didn't see its origins until the early 1980s.
You'll be able to, but it's preferable if you don't have to in your first few days of recovery. If it's possible to get your tongue pierced on a long weekend, holiday, or a break where talking can be minimized, it's a helpful idea. Due to the swelling, some slurred speech is common, but usually temporary. You may notice a slight lisp or more difficulty with lingual-dependent sounds like F, V, TH, S, L, T, and vowels.
You may feel uncomfortable and uncoordinated as you relearn some skills accommodating the new weight on your tongue and placement of your new piercing. Be patient with yourself and ease back into typical activities.
After your initial swelling has subsided, you will be ready to downsize to a shorter barbell for everyday wear. Switching to this smaller piece of jewelry is less dangerous for your teeth, gums, enamel, and the bones in your mouth, and will be lighter and easier to manipulate.
If you experience any discomfort caused by your tongue-piercing, consider trying smaller or differently shaped ends such as domes or flat discs, especially on the underneath side of your tongue. These ends take up less space in your oral cavity and are likely to feel more natural.