Despite the fact that multiplayer-heavy games like Splatoon 2 required the use of a phone app for online voice chat previously, it was discovered in early June 2018, around the time of E3, that the Switch actually had the ability to have Native voice chat, a feature that was finally implement with the help of Epic Games. It can be accessed by plugging in a set of headphones with voice capabilities. Nintendo enabled this feature on June 14th with the first game utilizing it being the widely popular Fortnite.

It is unknown why this feature was previously unused.
Contributed by PirateGoofy