Reading the new PHB's rules for determining a character's languages, I notice that many species are now effectively unable to take the languages that used to be their default options — Infernal for tieflings, Celestial for aasimar, Undercommon for drow, etc. Since these languages are classified as Rare Languages, it is no longer possible to learn them normally at character creation. Is there some kind of exception that I'm missing? If not, this feels like a bit of an issue.

Now only some features let a character learn a rare language and Species don't know any. I don't think it's necessarily an issue unless your campaign is very language-dependant.

The only feature I found in the PHB so far that lets you learn Rare languages is the ranger's Deft Explorer feature, at level 2 so even that can't let you learn these languages at character creation. Sure, it won't come up a lot, but a species being unable to learn its native language is still extremely weird.

A lot of characters also have thematic connections to the creatures speaking rare languages outside of their species. Why can't a Fiend Warlock learn Abyssal or Infernal? An Aberrant Mind Sorcerer, Deep Speech? A Cleric, Celestial? If the idea is that these languages are granted by other sources, then sources need to start actually granting them where they are appropriate.

The Druid's feature Druidic gives Druidic rare language.

The Rogue's feature Thieves’ Cant give Thieves’ Cant rare language and one other language of your choice.

The Wizard: Diviner's feature The Third Eye can read any language.

Quote from Lukipher >>

The only feature I found in the PHB so far that lets you learn Rare languages is the ranger's Deft Explorer feature, at level 2 so even that can't let you learn these languages at character creation. Sure, it won't come up a lot, but a species being unable to learn its native language is still extremely weird

Species don't have "native" languages. That's the point. What language(s) you speak depends on your upbringing

If your drow is an orphan raised by surface elves, why would they speak Undercommon?

Greetings Lukipher,

I made a similar post back in September that can be found HERE.

What I learned from that post and doing other reading, is that they made this change on purpose, and that if you want to give your character a Rare Language due to something in your backstory, etc., then you would work with your DM and make sure they are okay with it.
If your DM is good with the Rare Language (not sure why they wouldn't be), then you just manually add it to your character sheet after character creation.

Cheers!

But… why does the book not say this? The rules should not be relying on people overriding them with houserules, that's just sloppy design. At the very least I'd expect a clause along the lines of "Your DM might allow you to instead select a rare language if they agree it is appropriate for your character" somewhere.

To clarify — I don't care about the technical possibilities of a DDB character sheet, just about the rules themselves.

Quote from Lukipher >>

But… why does the book not say this? The rules should not be relying on people overriding them with houserules, that's just sloppy design. At the very least I'd expect a clause along the lines of "Your DM might allow you to instead select a rare language if they agree it is appropriate for your character" somewhere.

To clarify — I don't care about the technical possibilities of a DDB character sheet, just about the rules themselves.

 Because the rules aren't built to handle every last edge case. That would fall under house rules.

Quote from Athanar90 >>

Quote from Lukipher >>

But… why does the book not say this? The rules should not be relying on people overriding them with houserules, that's just sloppy design. At the very least I'd expect a clause along the lines of "Your DM might allow you to instead select a rare language if they agree it is appropriate for your character" somewhere.

To clarify — I don't care about the technical possibilities of a DDB character sheet, just about the rules themselves.

 Because the rules aren't built to handle every last edge case. That would fall under house rules.

I'd hardly call this an edge case. For a drow, for example, not knowing Undercommon would usually be more exceptional than the reverse. There are countless species and subclasses in this very book that are thematically connected to extraplanar creature types such as Fey, Fiends, or Aberrations, and it's only natural that a player using these options would also want to know the matching languages.

Quote from Lukipher >>

Quote from Athanar90 >>

Quote from Lukipher >>

But… why does the book not say this? The rules should not be relying on people overriding them with houserules, that's just sloppy design. At the very least I'd expect a clause along the lines of "Your DM might allow you to instead select a rare language if they agree it is appropriate for your character" somewhere.

To clarify — I don't care about the technical possibilities of a DDB character sheet, just about the rules themselves.

 Because the rules aren't built to handle every last edge case. That would fall under house rules.

I'd hardly call this an edge case. For a drow, for example, not knowing Undercommon would usually be more exceptional than the reverse. 

In the Forgotten Realms, maybe, although I'm not sure that would even be true for a drow PC

In Eberron or Exandria, though?

Right. The new PHB was also written to be pretty much setting-agnostic.

But in turn if you are playing a Drow that was raised in the Underdark, they don’t know how to speak the native language for some reason now. Instead of common and then two common languages, what I think they should’ve done was just give you three languages to choose from. From both common and rare languages. 

Yet another reason why the new PHB is so disappointing. How hard is it to add "Undercommon is considered a common language to you" in the Drow traits section?

Quote from Maruntoryx >>

Yet another reason why the new PHB is so disappointing. How hard is it to add "Undercommon is considered a common language to you" in the Drow traits section?

 It’s not hard, it’s just a bad choice because that is setting dependent. What if your world has no underdark? Or the drow in your world don’t live there?
Saying that presumes that every drow in every world — published or homebrew — is raised under the same circumstances. 
And if you want a drow from the underdark who does speak undercommon because that’s what makes sense for your character, you talk to your DM. 

I’m not sure how flexibility to allow something to work at different games with different lore is the sign of a bad product. Quite the opposite it seems.

Quote from Mourninstar >>

But in turn if you are playing a Drow that was raised in the Underdark, they don’t know how to speak the native language for some reason now.

If you are playing any character raised in the Underdark, you'll need DM approval to speak Undercommon. Which is how it should be