What ways can you give a creature the capability to speak?

Question

I am looking for ways in 5e to grant the capability of speech to a creature, ideally permanently.

To be specific, I am interested in granting an Artificer's Steel Defender and creatures like it the ability to speak. For instance the Steel Defender's stat block states it "understands the languages you speak", implying that it only understands them and does not speak them.

I am assuming that it is possible for the creature to use and attune to items.

Below are some ideas I have had after some initial investigation, but none seem sufficient and some are limited or dubious rules-wise:

Through Magic Items

• items that say "You can speak and understand X" (e.g. ring of elemental command, demon armor, efreeti chain, etc.)
  (Do these apply in our context of a creature with the stat block above? Specific v.s. generic - which is which here?)

• items that grant an Intelligence boost (e.g. headband of intellect)
  (Is boosting Intelligence enough to give a creature like the Steel Defender the capability to speak?)

• items that allow telepathy (e.g. helm of telepathy)
  (In general this isn't truly spoken speech. Oftentimes these are only communication with two people are there items that grant many?)

Through Spells

• awaken: limitation "Huge or smaller beast or plant"
• varieties of polymorph: limitation a transformation itself
• telepathic spells: limitation is telepathy is not true speech

(In general, these have the limitation of possibility of being dispelled and require a spellcaster.)

Older Editions

Also, I know in previous editions 3.5e Pearl of Speech existed, but I am interested in RAW 5e.

If you know of other ways that minimize the limitations involved and require few rare items, please share.

Answer 1

Your options are limited and will generally require DM approval

As you've said, there are limited options available to grant speech to a creature that doesn't have it within their stat block. And there are even further limits if we don't want to change what the creature actually is and just simply grant it the ability to speak.

In addition, there is also the concern about capability of speech. Some forms my be simply unable to talk, but I don't think that's actually in the rules anywhere or if magic supercedes that limitation. Whether or not the following will work is still very likely going to be up to the DM.

Spell(s)

The first option is the spell tongues (PHB, 283):

This spell grants the creature you touch the ability to understand any spoken language it hears. Moreover, when the target speaks, any creature that knows at least one language and can hear the target understands what it says.

The downside with tongues is that it only lasts an hour. That may be sufficient for whatever task is needed.

Magic Items

Here you've got some more options.

Ring of Elemental Command Since any creature can attune to an item, if you can find a Ring of Elemental Command (DMG, 235), your Steel Defender would be able to speak one of those languages (Auran, Aquan, Terran, or Ignan.)

The trick with this, of course, is that you'll need to be able to speak that language as well.

Ioun Stone of Language Knowledge This Ioun Stone from The Lost Laboratory of Kwalish, grants fluency in a language:

You are fluent in one additional language while this pulsating bit of red jeweled crystal orbits your head. The DM chooses the language bestowed by the stone.

It is up to the DM, though as to what language it is - so it may run into the same problem as the Elemental Command Rings.

Chronolometer from Acquisitions Incorporated which states:

The first time you attune to the chronolometer, you choose one language you don’t know. You subsequently know that language while attuned to the device.

Efreeti Chain (DMG, 167) grants the attuner knowledge of Primordial.

Same issue with you needing to know Primordial in order for communication to work.

Dragon Masks from Rise of Tiamat give access to Draconic.

Tinderstrike from Princes of the Apocalypse grants access to Ignan.

Drown from Princes of the Apocalypse grants access to Aquan.

Ironfang from Princes of the Apocalypse grants access to Terran.

Windvane from Princes of the Apocalypse grants access to Auran.

Grovelthrash from Explorers Guide to Wildemount grants access to Infernal and Abyssal.

Belt of Dwarvenkind (DMG, 155) grants access to Dwarvish.