Lat. introvert-/introvers- and extrovert-/extrovers-
Finally, there are a number of English-Spanish cognate words that would seem to derive from the root ‑vĕrt‑ and other prepositional prefixes, namely Eng. introvert(ed) and extrovert(ed) and Sp. introvertido and extrovertido. Curiously, however, there are no verbs such as Eng. *to introvert or Sp. *introvertir to go along with those other words. Also there were no verbs *introvĕrtĕre and *extravĕrtĕre in Latin that they could have come from, though there very well could have been, since intrō‑ ‘on the inside, within, to the inside’ and extra‑ ‘outward, to the outside’ are legitimate Latin prefixes, cf. Eng. introduction and extracurricular. These, however, are New Latin words, words created from Latin word parts to look like Latin, but only as adjectives and nouns, not as verbs (cf. Part I, §8.5).
The adjective extroverted was created and first used in English in the 17th century to refer to something protruding in a technical sense in metallurgy. There was even a verb to extrovert created and used in writing only once, in the early 19th century, with the meaning ‘to turn or thrust outwards’ (OED). By all accounts, these words were extremely technical, fancy and rare, but then something happened that would catapult these words into fame.
Around 1918, German psychologist Carl Jung created (or perhaps borrowed) the words as extravertiert and extraversion in German, with the current psychological sense relating to an outgoing, socially confident personality, on the basis of Latin extra‑ and vĕrtĕre.[i] These German words were soon borrowed, with the new sense, into English and Spanish.
English borrowed the German noun extravertiert as extravert (with an a), though soon the spelling was changed to extrovert under the influence of the opposite word introvert (the original extravert spelling is still used in the psychology field). From the noun, English derived the adjective extroverted and the noun extroversion. Spanish too borrowed German extravertiert as extrovertido, as if it was a past participle of a non-existent verb *extrovertir, which can be both an adjective and a noun, and the noun extroversión, to refer to the condition.
Likewise, the verb to introvert and the derived adjective introverted had already been used in English by the 17th century as New Latin words, created on analogy with other existing prefixed Latin vĕrtĕre words, with the meaning ‘to turn inwards’, referring to an activity of the mind or the soul. A sense of physically turning inwards appeared a century later in English for these words. But, again, it was Carl Jung’s introduction of these new psychological personality traits in the early 1900’s that is responsible for the new senses and the popularity of these words. Spanish has borrowed introvertido, which is both an adjective and a noun, whereas English has the noun introvert and the adjective introverted. Both languages also have the cognates Eng. introversion and Sp. introversión to refer to the psychological condition in question.