We here introduce you to the Undercommon 5e language, which is unknown to most people. The Underdark uses Undercommon as a trade language. Almost every language has a specific creature it should be used with. There is an easy to use language used by the creatures of the Underdark, derived from the common 5e language.
The animals of the Underdark spoke only the Underdark language. The 5e language may be blended with the minimal form appropriate for the specific sector. Surf languages have troll languages with perfect languages in their surf area. Underdark sentient species speak a commerce language endemic to the Underdark. Drow influence and elven writing were present. Traders from Underdark spoke the language.
It is based on the drow language at first. Drow slaves invented this language so they could communicate with each other, just like other slaves of other races. By that time, it had become a trade language between the minimum races of the Underdark, since many could speak at least one of them. Frequently considered an insult by the Xanalress to speak to the drow because they use this tongue. It is not uncommon for the drow of Arelith to use drow words in their sentences and conversation.
Based on: Drow 
The script is in Elvish
Traders from the Underdark
The script is in Elvish
The language type is language
Speakers Typical of Underdark Traders
Gnolls, who are not originally from the Underdark and were held as slaves by the Drow, have no idea what to make of this strange language. You do not have to be an Underdark native to play your character. If you don’t speak the language, you cannot play. The Drow surface is sometimes a point. I never took the time to learn the language of the lower races living in the Underdark. The Drow can be bigots sometimes.
Undercommon vs Common – what is the difference
Drow is the common language of the Underdark, and it is a dominant language. Elvish sounds like it may have been borrowed from other races of the Underdark, but it’s harsher and may contain loan words from those languages.
Common uses simple and familiar script, while undercommon uses elvish script.
Common languages are universal languages, meaning most people can speak them. Among the common languages, the under common language has the most specific words, but you cannot read nor write it.
On a good day, your DM may give you Undercommon for free if you have a strong desire to identify it. On the other hand, it might be helpful to have something to do.
What is Undercommon Speech?
The Underdark’s commerce language is Undercommon, also Deep Speech 5e. Surface Common, Drow, and Dwarven elements combine to create this. For good measure, some Goblin slang and other low terminology are thrown in. Despite this, the Drow language is the primary basis.
What does Undercommon Translator mean?
The graphic below demonstrates how this under common is written in the Espruar alphabet, including the English alphabet and translations from “every day” (english) to “under common”.
Kenku 5e (5th Edition) Race in D&D Races