Odd that this is not labeled on this page as being a ritual spell.

It is now, not sure if it didn’t when you posted this.

Casting Spellword is:

Lingus Mentalus  

Last night there was a tag under "Available For" and listed "Archivist" after Wizard. Same with a few other divination spells. Reference has been removed now.

Does this give you the ability to speak languages 

No, just to understand them. You want the spell Tongues: https://www.dndbeyond.com/spells/tongues

It's the little R next to the casting time.

Aye they added that after my comment

This mixed with the lip reading from observant with invisibility is amazing for stealth intel gathering.

Just added this to my Arcane Trickster but it's not showing up as a ritual.

I can never understand why this spell isn't available to clerics, at least knowledge clerics. Since a Clericc cast Tongues and all that.

I find taking the 'Ritual Caster: Wizard' feat a fantastic addition for the cleric.You theoretically any ritual the Wizard can learn, provided your DM gives you a way of accessing them. It gives you Comprehend Languages, as well as some very useful rituals like Find Familiar, Unseen Servant, Tiny Hut and Alarm.

The other rituals are pretty handy too, though some like Illusory Script and Magic Mouth might be a little niche.

I like how Clerics can cast Tongues but not Comprehend Languages, not even the Knowledge Cleric. Very cool.

Quote from mjames_74 >>

This mixed with the lip reading from observant with invisibility is amazing for stealth intel gathering.

 No it isn't. Well, it is, but it doesn't interact with lip reading. "... spoken language *that you hear*." 

I'm late, but Arcane Tricksters aren't ritual casters.

Quote from Tyranthraxes >>

Casting Spellword is:

Lingus Mentalus  

 What is it with you and your casting spellwords? And can I have a list of them?

Hypothetically, would it work if I Detect Thoughts on a creature that think in a different language and Comprehend Languages on myself?

Quote from LolChocobo >>

 

Hypothetically, would it work if I Detect Thoughts on a creature that think in a different language and Comprehend Languages on myself?

 

 

Beyond 20

 

 

 

 

 

tl;dr: This won't work, but you might be able to use detect thoughts anyways.

The Bad News:  I don't think this would work. Comprehend Languages lets you understand "spoken language that you hear." Detect Thoughts describes how you read a creatures mind and know its thoughts, but those thoughts are not A) spoken by the target, nor or they B) heard by you. Comprehend Languages doesn't seem to apply here.

The Good News: Detect Thoughts does not specify that you need to share a common language. It does not work on a creature who "doesn't speak any language" but does not specify you need a common language. Unfortunately this leaves some ambiguity, because while it does say you can "read" and "learn" the creatures thoughts it never explicitly says you have the ability to understand them. This leaves a lot of room for interpretation either way. To complicate things even further, some spells specify they don't require a common language (e.g. Telepathic Bond) other spells specify that they do require a common language (e.g. Modify Memory) so we can't even go off the logic that they mentioned X there, so if they meant X they would have mentioned it here too, therefore we can assume not X. Ultimately I'd argue that Detect Thoughts A) involves mind to mind contact and B) is a divination spell, both like Telepathic Bond but both unlike Modify Memory (which is verbal and an enchantment) so I would probably interpret Detect Thoughts as working more like Telepathic Bond and not requiring a common language, but it's based on really, really slim evidence. It's pretty much a toss up.

A lot of people might overlook a very important part of the Comprehend Languages spell. The spell lets you you understand the literal meaning of any spoken language that you hear. Emphasise on literal meaning. While it might not seem very important for someone who only speaks one language, but let me put it this way: for native english speakers, if you hear "tell me about it" after you rant about something, you understand that the listener feels the same way as you, while my first reaction would be to say "but I have just done that, were you not listening?".

Is it an error that Clerics can't cast Comprehend Languages?
I have a Knowledge domain cleric and realised that there's actually no way for him to read foreign languages! Channel Divinity: Knowledge of the Ages grants skill/tool proficiency for ten minutes, but I don't think languages a "skill"? (In RAW game terms!)
I was thinking that when he gets into third level spells then Tongues would do it, but that's spoken comprehension only.
Does this seem like a big gap to anyone else? Or am I just a munchkin?