Two sessions into my first game with some IRL friends and I feel pretty awkward roleplaying as NPCs - we're all sort of new so there are some chuckles from the awkwardness but it feels really hard to know what to say to the players in a way that doesn't sound, well, goofy. Do any more experienced DMs have any tips for shyness/awkwardness with roleplaying NPCs?

Enjoy the goofy! Play it up! The most important part of dnd is fun. It’s all right for the NPCs to sound silly.

Don’t stress! New players are especially forgiving- many of them will probably also be struggling with roleplaying themselves.

Concentrate on one characteristic for each NPC and show it in their speech. Are they bold? Have them make brave, ridiculous statements. Are they shy? Speak quietly and nervously.

Practice is also important- the more you play, the more you will get used to it, so don’t worry.

Welcome to the game! :)

I find that using third person is more natural.

GM: The gate guard stops you politely and asks your business in town.
vs
GM: "Well met travellers, what brings yer to our town today?"

I am bad at expressing the cues that apply to the various social skills, so if I just state things outright then it makes the game easier for everyone.

GM: The guard is bored, not paying attention to you. Players can conclude this is a good opportunity for persuasion or deception.
GM: The guard looks at your expensive gear and jewellery. Players can conclude this is a good opportunity for bribery.
GM: The guard looks up at you, and shrinks back when he sees how many of you there are. Players can conclude this is a good opportunity for intimidation.
GM: The guard stands firm and looks you in the eye. Players can conclude this is probably no opportunity for deception or bribe.

Thanks so much! I’ll definitely try that out - I think trying to keep track of a lot of complexities to each NPC was leading to a few trip ups, rather than a few basic traits to just bounce off of. 

as a different point of view I dont do voices, I don't do faces and I don't really do in depth role play mainly because i know it will detract rather then add, in 20+ years I have never done any of that. What I do is get across the important aspects of the NPC, I give detailed descriptions, I describe the voice (rather then doing it) and then i have a conversation with the player. I don't do 3rd person but i dont try and go all in.

If you are new I would say as a starter try that approach and focus on the interaction and learning how to play the scene you can always then work on accents later. 

Remember, there are different ways to RP. Most DMs don't use first person ("I hand you the key") because DMs play multiple characters, but there are different ways to do 3rd person RP. One way is to provide the dialogue: "Avast, ye matey," growls the pirate captain. "Where be ye headed?" 

The other way is to just summarize it: The pirate captain, in a voice heavy with ale and a foreign accent, asks where you're headed.

Both of these are valid ways to RP, and I tend to slip between them. Some NPCs who I consider important, I'll do actual dialogue for. Most NPCs, though, are simply not that important, and I don't do dialogue for them -- shop owners, gate guards, innkeepers. Unless the players start doing the dialogue with me for some reason, I mostly summarize. Even there, the level of detail in which I summarize is going to vary from glossing over, when just walking past gate guards showing ID (again, unless there is something important going on), to more detail when talking to the town Prefect about a murder.

Now -- I say these things because often, it's trying to do voices, accents, and literal dialogue (the first example I gave) that feels very awkward to DMs. If you are feeling that way, it may help to just summarize what the guards are doing, rather than trying to "talk like them."

For example -- I am a terrible singer and I am not good at making up songs on the spot. But the party is in a Grey Elven town right now and the Grey Elves in my world are very musical and they sing as they go about their day. I did not make up any songs for this. I just described how as they walk along the street, they hear the elves singing about their day. Elves passing by those who are, say, repairing a roof, will pick up the roofers' song and join in a bit and then switch to another song as they walk past a shop keep... And that as they walked, they heard the elves peppering in lines about the party, so they heard a line about the old dwarf with the large belly, or the little gnome with the squirrel on her shoulder (2 of the party members). This conveyed exactly what was happening without me saying one line of literal dialogue and without me singing one note -- both of which I would have found very awkward to do. My players got the idea, and loved it -- one even said, "If this character dies, I'm making up a singing Grey Elf."

https://www.youtube.com/watch?v=-Ek5GK5jcss

I've used this video so much. I love it. I've also passed it on to many people. Please enjoy!

Yup, awesome video.

In some ways it’s one of those “only way out is through” situations, or “fake it till you make it” if you prefer. You just keep doing it, and your confidence will grow and everyone will accept it as normal. 
Also, I usually don’t do voices. Maybe one or two very important, recurring NPCs will get a voice. Others might get a vocal tic, like someone who says ummm a lot, or clicks their tongue — just enough that players will remember them. Most people: guards, shopkeepers, bartenders. They don’t get anything special. Don’t feel like you need to be on the level of crit role or other streamers, just relax and have fun with it.

First of all, I would like to echo the others in welcoming you to the hobby. Well met. May your campaigns be long and many, and your players happy. (And not wangrods.)

Now, onto the business at hand. I talk about what the NPCs do in 3rd person, but I speak for them in 1st person. I do it like how “mom did the voices” when she read to me as a little kid.

Some giggles are to be expected, but if you keep doing it that’ll end soon enough. After a couple sessions it stops being unusual and just becomes the thing that happens. Also, the more you practice, the easier it gets. So keep “doing voices” and inevitably doing voices will bet easier.

I tend to suck at accents. (I mean, if I try to do Eastern European/Russian it sounds like Apu Nahasapeemapetilon attempting to make an “in Soviet Union” joke. Nonbueno.) So most often I change my voice in other ways to “do the voices.” Maybe I’ll go deep for an Orc or Hobgoblin NPC, high for a Goblin or Kobold. I’ll likely go reedy for little old men, or gravelly (like Batman) for a hard-bitten sort of person. Or softer for a young woman or clack my teeth like an alligator when I do a Dragonborn. Stuff like that.
     Now, I’m a 40 yer old man with fairly deep voice naturally, so I can only ever get so high and so soft before it’s ridiculous and my throat hurts. so I only change my voice as much as is comfortable. I don’t actually have to sound like a young woman though, so it’s okay. I’m just making it enough of a distinction to get the impression across. I just need to make sure that young Clara Bodkin sound distinctly different enough from my own voice that the players can tell when I’m speaking and when she is. I’ll tell ya though, henever there are more than three NPCs in the same conversation it gets reeeaally hard to pinball myself back and forth between them.

Another thing that makes it easier is to also incorporate mannerisms and regional commonalities to complement your voices. In one region it’s really cold so folks in that region tend to keep the insides of their cheeks against their teeth when they talk so the cold air doesn’t affect them. (Like when you eat iced cream and your teeth hurt from the cold.) When I do that I start to sound more Minnesota or southern Canadian dontcha know? In another area folks keep their jaws clenched very rigidly for whatever reason. (Maybe their culture considers it rude to show folks the inside of your mouth or something. 🤷‍♂️ Who knows?) Whenever I keep my jaw rigid like that my speech starts to get that quality that people use to caricaturize the “Harvard accent.” In another are people talk reallyreallyfast an’allatheir wordstarta runtogether.
     Or in another area a particular phrase or colloquialism might be remarkable apparent. Like, how the phrase “fo’getabout it” gets used a lot by New Yorkers. So maybe folks there finish a lot of sentences with “if you catch my meanin.’” Or perhaps they have a particularly recognizable regional mispronunciation for a few words, like how people in Philly drink “wooder” instead of water, but in Boston they drink “watah.” So maybe somewhere they say “yar” instead of “yeah,” or something similar… if you catch my meanin.’ 😉

So my overall advice is:

• Don’t worry about the “awkwardness” so much because it’ll pass soon enough.
• Practice. It’ll get easier with practice.
• There are easier ways to do voices, and there are harder ways. Do the easier ones, at least in the beginning. Don’t go nuts trying to a bagillion voices in hundreds of accents. (Nobody can, not even Mercer.) Instead, just do what you can do that won’t sound too forced or hurt your throat.
• Use different techniques to augment the strait voices to augment whatever voices you do.  My “not so high,” and “not so soft,” young woman voice sounds different when a young woman from “Coldlandia” speaks than when one from “the Leagues of Ivy” speaks. And they both sound different from the the young women of “Reallyreally Fastland.” (Well, different enough anyway.)
• Use colloquialisms, other figures of speech, and even dialectic patterns to turn a handful of voice changes into a myriad of variations. 
• Don’t worry about making them all completely different, “different enough” is all you really need. (And more than most DMs do.)

And if none of that 👆 helps them skip the voices. (You don’t really need them anyway.)

Good luck!

Double shot of whiskey before the session works.