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

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 Artificers Steel Defender and creatures like it the ability to speak. For instance the Steel Defenders stat block states it “understands the languages you speak” implying that it only understands them and does not speak them. I am assuming the possibility of the creature being able to use and attune to items.

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

Through Magic Items

-“You can speak and understand X” : Ex. 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?)

-Intelligence Boost: Ex. Headband of intellect

(Is boosting intelligence enough to give a creature like the Steel Defender the capability to speak?)

-Telepathy: Ex. 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 spell caster)

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.