Running adventures with varied races of NPC, I run into a lot of times where I simply say "It sounds like they're speaking Elvish/Orcish/etc etc". I'd like to know if perhaps there are descriptions of what the languages sound like in any published material, so that I can instead describe vaguely what the characters hear.
5th Edition races often briefly describe languages
Races that start with specific languages often include a short description of the language. For example:
Elvish, from the Elf traits :
Elvish is fluid, with subtle intonations and intricate grammar.
Draconic, from the Dragonborn traits:
Draconic is thought to be one of the oldest languages and is often used in the study of magic. The language sounds harsh to most other creatures and includes numerous hard consonants and sibilants.
Dwarvish, from the Dwarf traits:
Dwarvish is full of hard consonants and guttural sounds, and those characteristics spill over into whatever other language a dwarf might speak.
Orcish, from the Orc traits:
Orc is a harsh, grating language with hard consonants. It has no script of its own but is written in the Dwarvish script.
Primordial, from the Genasi traits:
Primordial is a guttural language, filled with harsh syllables and hard consonants.
Previous Editions and further research
The Manual of the Planes from 3e briefly describes Auran, Terran, Ignan and Aquan (emphasis mine):
The native language of the Elemental Plane of Air is Auran, a breathy, leisurely tongue that sounds like a long, slow exhalation.
The native tongue of the Elemental Plane of Earth is Terran, a deep rumbling tongue that vibrates through the listener like a tremor.
The native language of most inhabitants of the Elemental Plane of Fire is Ignan, a sharp, hissing and clicking language.
Natives of the Elemental Plane of Water speak Aquan, a flowing, subtle language filled with double meanings and hidden puns.
Abyssal and Infernal seem to be both described in Faces of Evil: The Fiends (2e), as referenced from the wiki:
Abyssal: Lower-ranking demons spoke using sounds like the barking of canines, while the speech of more refined demons sounded like softly droning ocean waves mingled with the violence of a swarm of angry hornets.
- Infernal includes 4 different forms, described in the referenced sources (omitted here for brevity)
It was described as beautiful, yet alien in nature, since it developed among beings with thought patterns very unlike those of humanity.
Note that this list is not exhaustive, I'm sure there's a lot more to be found in the vast publication history of D&D (and even on that wiki), I just looked for some of the more common languages.