dep. in English?

[Lavrentivs]

Is there any deponent verb in English?

[adrianus]

There isn't. // Non est.

[Sceptra Tenens]

By a stretch of the imagination, although not recognized as such by experts, you might consider such terms as "to be used to something" or "to be born" as deponent. "To bear", at any rate, refers to being pregnant rather than giving birth in the present tense, so the passive sense has diverged from the active.

[adrianus]

Minimé. Unum adjectivum est; alium justum passivum.

In "to be used", the "used" is adjectival, since we can say "to be too used" and "to be very used",—something you can only do with an adjective.

"To be born" is a simple passive of the verb "to bear", when it means "to bring forth, produce, give birth to" (OED): "She bore the baby on that day" vs "The baby was born on that day".

[Sceptra Tenens]

In "to be used", the "used" is adjectival, since we can say "to be too used" and "to be very used",—something you can only do with an adjective.

But I also hear "to be getting used to something". I wouldn't necessarily say that adjectival qualities make it adjectival - verbs phrases like this are rare in English, and I would expect them to have their own peculiarities.

"To be born" is a simple passive of the verb "to bear", when it means "to bring forth, produce, give birth to" (OED): "She bore the baby on that day" vs "The baby was born on that day".

Still, one can say "a baby is being born", but "she is bearing a baby" is unused when referring to birth. This is one peculiarity that is causing the two senses, in my eyes, to diverge. I've always "felt" it as an active verb, and I don't think that I'm the only one.

That doesn't make it a true deponent, but I do think that it could very well become one.

[MatthaeusLatinus]

Isn't "to be born" an example of the middle voice?

[Damoetas]

You will go far astray if you try to use Greek and Latin grammatical categories to describe English.

[adrianus]

"to be getting used to something". I wouldn't necessarily say that adjectival qualities make it adjectival

Synonyma exacta "getting" vocabuli anglici // exact synonyms of "getting" here: "becoming", "beginning to be", "growing", "turning into one who is"

Synonyma exacta "used" vocabuli anglici // exact synonyms of "used" here: "accustomed", "habituated", "acclimatized", all of which can take + "too" or "very".

"to be born", "to be seen", "to be awoken", "to be heard",—all are verbal passives (though you can use "born again" adjectivally in "to be very born again") // passivâ voce omnia haec accuratè sunt (etiamsi adjectivus est usus per exemplum citatum).

"she is bearing a baby" is unused when referring to birth.

It certainly can be (and was), though "giving birth" is more common these days.
Certùm id dici licet, etiamsi "giving birth" moderniús.
"She bore a baby on that day, and when she was bearing the baby upstairs, the father was distributing cigars downstairs."
"She bears a baby on that day, and when she is bearing the baby upstairs, the father is distributing cigars downstairs."

It is perhaps a little egocentric to view "to be born" as an active verb in English and leave out the mother's agency.
Activâ voce nascor verbum anglicè concipi et matrem agentem omitti, nonnè id paenè cupiditatis sui vestigium est.

[Sceptra Tenens]

You will go far astray if you try to use Greek and Latin grammatical categories to describe English.

Fair enough. I found myself getting carried away with terms like "dative" and "ablative" after beginning Latin, when the cases don't fit well in English.

Synonyma exacta "getting" vocabuli anglici // exact synonyms of "getting" here: "becoming", "beginning to be", "growing", "turning into one who is"

Synonyma exacta "used" vocabuli anglici // exact synonyms of "used" here: "accustomed", "habituated", "acclimatized", all of which can take + "too" or "very".

Still, I think that it is significant that it feels like a verb. Perception, if it isn't reality itself, certainly has the potential to become it in the hands of native speakers.

They aren't "exact synonyms", though. None of these, not even "used", are adjectives - they are participles, and can be made active.

"I am accustomed to it" ~ "I accustomed myself to it" - good
"I am habituated to it" ~ "I habituated myself to it" - good
"I am acclimatized to it" ~ "I acclimatized myself to it" - good
"I am used to it" ~ "I used myself to it" - bad
Correct (though casual) active - "I got myself used to it", in which "used" is still a participle. This "got", when used with "myself", can't be replaced with any of those alternatives you offered.

Food for thought.

It certainly can be (and was), though "giving birth" is more common these days.
Certùm id dici licet, etiamsi "giving birth" moderniús.
"She bore a baby on that day, and when she was bearing the baby upstairs, the father was distributing cigars downstairs."
"She bears a baby on that day, and when she is bearing the baby upstairs, the father is distributing cigars downstairs."

Those sound dated to me. It seems that the word "bear" itself is slowly falling out of use.

There are other things as well.

"I was seen by her" ~ "She saw me" - good
"I was awakened by her" ~ "She awakened me" - good ("awoken" cannot have an agent)
"I was heard by her" ~ "She heard me" - good
"I was born by her" ~ "She bore me" - good, BUT the meaning is different than "I was born". When I say "she bore me", or "I was born by her", I mean "she carried me". There is no way, at least in my idiolect, that I would take that as referring to birth - it would be implied, to be certain, but not expressed. Perhaps this isn't true for everyone, but it is significant that it is true for some native speakers.

(ETA - "he was born by her" even looks wrong to me. My mind is telling me "borne, borne!", which shows how this is processed in my head)

It is perhaps a little egocentric to view "to be born" as an active verb in English and leave out the mother's agency.
Activâ voce nascor verbum anglicè concipi et matrem agentem omitti, nonnè id paenè cupiditatis sui vestigium est.

When I learned English as a child, I didn't learn the mechanics of birth along with the term "to be born". The Romans did the same thing - nascor is said to have derived from gnasco, an active verb. The Romance languages in turn use the descendent of nascor as active. Why should English have to retain the grammatical agency of the mother?

Let me reiterate now that I am not saying that they are deponents by the strictest reckoning, but that they are potential future deponents.

[adrianus]

They aren't "exact synonyms", though. None of these, not even "used", are adjectives - they are participles, and can be made active.

It is an adjective because you can qualify it with "too" or "very". Participles can be adjectival and verbal. You can often distinguish the adjective from the verbal form when you can put "too" or "very" in front of them. Sometimes you must be content with ambiguity: "they were married".

Other tests for "used" as an adjective in "to be used": (1) "to be unused"—you can't prefix "un-" to a verbal form there; (2) substitute "seem", "look" or "remain" for "be", as "to seem used", "to look used", "to remain used" (after Huddleston and Pullum, Cambridge Grammar of the English Language, pp.1436,1437).

Adjectivum verum quod "too" vel "vel" antecedere potest. Et adjectivum et verbum participium. Nonnunquam adjectivus usus distinguatur per talem modum. Nonnunquam ambigua anglicè restat res, utputa "they were married".

"he was born by her" even looks wrong to me. My mind is telling me "borne, borne!", which shows how this is processed in my head

43. a. Of female mammalia, and esp. women: To bring forth, produce, give birth to (offspring).
...
44. The various forms of the pa. pple. had formerly no distinction of sense. In the earlier part of the 17th c., these were borne (usual), born, bore (rare). About 1660, borne (the only spelling in Shakespeare folio of 1623) was generally abandoned, and born (cf. torn adj., worn adj.) retained in all senses, with bore as a frequent variant (the latter perhaps not in sense of nātus). Dr. Johnson, in his various edd. from 1751 to 1773, says under bear n.1, ‘part. pass. bore or born,’ and the same is found in other dicts. and grammars of the period. But c1775, a different usage (which some writers or printers had observed as early as 1750) was established: bore (common in Addison, Swift, Thomson) was abandoned, borne was reinstated, and now used as the ordinary form, and born was restricted to a specific sense. Thus, borne is now the only pa. pple., active or passive, in senses 1  – 42   (he has borne a burden, the tree has borne fruit, the testimony borne by him); it is also used in sense 43 in the active always, and in the passive with by and name of the mother, that is when it has the literal sense of ‘brought forth.’ Born is used only in sense 43, and there only in the passive, when not followed by by and the mother; it has rather a neuter signification = ‘come into existence, sprung’ without explicit reference to maternal action; hence it is the form used adjectively, and figuratively. Cf. ‘She had borne several children, the children borne to him by this woman, born of the Virgin Mary, born in a stable, her first-born son, a lady born, new-born zeal, a flower born to blush unseen’.

[Lavrentivs]

Isn't every perf. part. adjectival?

[adrianus]

Participles have the nature of both adjectives and verbs but they can be more like adjectives in one place and unlike verbs, and more like verbs in another and less like adjectives.

Natura participiorum est simul et adjectivi et verbi, quae in uno loco assimilat adjectivum non verbum, alio loco verbum non adjectivum.

Notice the difference:

"They were married by the minister on a certain day" (verbal be-passive)
"They were married for twenty years" (adjectival passive) will not mean "They were married repeatedly for twenty years" but "they were in a state of marriage for twenty years" and is the same structurally as "They were happy for twenty years."

Sometimes the difference is clear between the natures when you apply the tests mentioned.
Clarum nonnunquam, examinibus supra citatis factis, discrimen inter formas.