Most Romance languages don't have /x/ (like the j in hijo), nor did Latin. Where did Spanish /x/ come from? Internal development, Arabic influence, or something else? Since Moroccan Arabic also has /x/, one would suspect Arabic influence; but perhaps that is simplistic.

  • Also note that in Galego (and maybe in Catalan) and Portuguese the spanish /x/ is usually (or in all cases) also written x (Xacobeo, caixa) but the pronunciation is little different (like english "sh").
    – Tomas
    Feb 17, 2012 at 12:31
  • Also Spanish has its written "x" (texto, Mexico), but I think this is exceptional (?)
    – Tomas
    Feb 17, 2012 at 12:32
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    I seem to recall that in Brazilian Portuguese "rr" has a sound like Spanish "x"/"j". Another romance language with lots of Arabic influence was Sardinian, so it might be worth looking at. Also /x/ differs from the more mundane seeming /ɣ/ mostly by voicing so that could also be interesting to investigate. Feb 17, 2012 at 12:52
  • 3
    @hippietrail, <rr> is realized in several ways in Brazilian Portuguese (depending on the geographical region, age, social class, etc). Among them, I have heard [ʁ], [h] and even [χ], but never [x]. Feb 17, 2012 at 21:57
  • Yes the question was about /phonemes/ though rather than [phones] and sounds travelling between unrelated languages will rarely be unchanged. These four sounds and others all tend to overlap in one language or another at the phonemic level. Feb 18, 2012 at 0:36

4 Answers 4


Spanish did have Arabic influence but it seems that the jota (the name for the letter j in Spanish) came from Latin, going through some variations.

An hypothesis, provided in "Introducción a la historia de la lengua española" by Melvyn C. Resnick, at the page 38 (Scroll down until you read «Podemos postular...» going onwards) explains the path from ōcŭlu to ojo:

  1. The [k] (letter C) voices and becomes a [g]: ōcŭlu > ogulu
  2. The post-tonic1 vowel falls: ogulu > oglu
  3. There is a "shift" from the final -u to -o: oglu > oglo
  4. The [g] "vocalizes" (i.e. it becomes a vowel sound) and becomes the semivowel [y], called Yod letter's name from the Hebrew alphabet: oglo > oylo
  5. The yod and the semivowel exchange position (called metatesis in Spanish): oylo > olyo
  6. The group [ly] gives the [ l̺ ], similar to the Spanish "ll": olyo > ol̺o
  7. The [ l̺ ] becomes the semivowel [y]: ol̺o > oyo
  8. The semivowel [y] intensifies as the g in the French rouge, the IPA is [ž]: oyo > ožo
  9. Following a general tendency from the Spain of the XVIth century, the sound becomes voiceless2, the IPA is [š]3: ožo > ošo
  10. During the XVIIth century, in Spain, the sound [š] is lost, and the current "jota" sound with the modern pronunciation is originated. It's the same sound from the south american Spanish, the IPA is [χ]: ošo > oχo
  11. In the southern Spain and the northern countries of south america, the [χ] results in [h]: oxo > oho, written form ⟶ ojo.

The evolution of mūlǐēre > mujer and fīlǐa > hija follow the same pattern as ōcŭlu > ojo [...], but not all words with such features have the same result.

For now, I haven't found other clear references but there are some hints that confirm the process described above. If you want, I can find some other references to further back up this process.

I made a search about the possible causes of this "velarization", but little is there. Especially one source that could hold this information is not (fully) available online, which is "Historia de la lengua española" by Rafael Cano Aguilar. The chapter that interests us is the number 32, titles "De las sibilantes y palatales antiguas a las «ces», «eses» y «jotas» modernas", but the book stops around the chapter 29 in that preview, so it's not possible to see what is written there. (If someone can access those pages in that preview, please comment.)

Other texts I've consulted are "Variation and change in Spanish" by Ralph John Penny, "A history of the Spanish language", always by R.J. Penny, "Historical romance linguistics: retrospective and perspectives" by Randall Scott Gessa and Deborah L. Arteaga, and "Historia de la lengua española" by Rafael Lapesa, but none of these talked about the causes, although they confirmed that passage from [ʃ] to [χ].

The only place that mentions the (possible) causes is the wikipedia article about the "Adjustment of the sibilants in Spanish" 4, but I haven't found anything that confirms or denies the information being found there, although I think they are a good starting point if you want to further investigate.

For those who don't know Spanish, I'll summarize the main points of the section "Posibles causas" (possible causes):

Phonetic changes are natural processes in all languages. Although there are phonetic laws that act outside of the linguistic genealogy boundaries; [...].

When treating phonetic changes or evolution, we must take into account that there never is a single reason, rather some that "act together". Among the causes, linguists distinguish between internal and external causes, [...]. In this case, linguists believe that the loss of those voiced sounds was due to a spanish-basque bilingualism [...], while others think that it was an internal simplification due to structural causes.

[...] Taking into account the fact that the /s/ was an apico-alveolar, there wasn't much difference between that and /š/. For this reason, Spanish speakers, in order to keep the two phonemes distinguished, started to bring "back" the place of articulation, transforming the latter into a velar. [...]

Hope this helps. Judging from what I found, we know fairly surely how we got this sound "out of nowhere" but we don't know the causes for sure yet. If you don't feel satisfied, I can try to make a deeper research.

1: I think postónica refers to post-tonic.
2: "Ensordecer" literally means "to deafen", but I think here it's mean as "to devoice/to become voiceless".
3: [š] = [ʃ]
4: The original title of the article is "Reajuste de las sibilantes del idioma español".

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    @Petruza As far as I know, the previous X (around the XVIth century) was pronounced as /ʃ/, and you can see that in "Don Quixote" which was read as "don kee-shot-eeh", which survived in French and Italian (respectively, Don Quichotte and Don Chisciotte".
    – Alenanno
    Feb 18, 2012 at 13:44
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    Wow, didn't know that, I guess makes sense as Portuguese still has X = /ʃ/
    – Petruza
    Feb 20, 2012 at 12:42
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    The phoneme /x/ in Spanish has two allophones: [x] and [χ]. with the latter occurring naturally when /x/ precedes /o/ or /u/. This [χ] is uvular, not velar as [x] is. So Don Quijote is [d̪õ̞ŋkiˈχo̞t̪e̞], enjuto is [ẽ̞ɴˈχuto̞], and the Asturian city of Gijón has both sounds: [xiˈχõ(ŋ)]
    – tchrist
    Feb 25, 2012 at 7:07
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    Also, with the merger of /ʃ/ and /ʒ/, modern /x/ can be a reflex of either. The spelling change of the voiceless ones to ⟨j⟩ is presumably due to the merger. The /ʃ/ or /ʒ/ can come from various sources besides [lj]; consider jefe (presumably from French chef /ʃ/), jamón from French jambon /ʒ/, reloj (Wiktionary says Catalan with [dʒə]), caja from Latin capsa (probably via an intermediate form similar to Portuguese caixa), jibia from Latin sēpia, lejos from Latin laxius [ksi]. Jan 25, 2013 at 10:26
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    @Alenanno: Some of the first 6 steps are wrong. Also step #3 isn't really relevant and probably occurred after step #6. Step #2 definitely happened first; words like oclu(m) are directly attested and are also the ancestor of Italian occhio. I suspect that the pattern was actually oculum > *ɔculu > *ɔclu > Proto-Romance *ɔcʎu > Proto-Western-Romance *ɔʎʎu > Spanish *ɔʎʎo > *oʎʎo > *ojjo > *oddʒo > Old Spanish odʒo > oʒo > oʃo > oxo. Note that single /j/ e.g. in ''mayor'' was unaffected. Nov 6, 2013 at 3:51

To rephrase the first answer above: Spanish /x/ comes from earlier /ʃ/ by a process of backing. Old Spanish of the 1300's had the sounds /ʃ ṣ ts ʒ ẓ dz/ where /ṣ ẓ/ indicate apico-alveolar sibilants. By the 1400's this had become /ʃ ṣ s ʒ ẓ z/ with apico-alveolar /ṣ ẓ/ vs. lamino-dental /s z/ (similar to English). The sound /ṣ/ was quite similar to /ʃ/ on the one hand and /s/ on the other. Usually a language with tricky-to-distinguish sound pairs would eliminate one of the two (cf. Portuguese which once had the same sounds but changed ṣ > s and ẓ > z, still distinguished in spelling: intervocalic ss vs. ç, s vs. z). But in Spanish, before such a change could happen, a different change happened, with the voiced sounds becoming unvoiced. This put a high load on the remaining sounds /ʃ ṣ s/, and so most dialects of peninsular Spanish "solved" the similar-sound problem without any mergers by separating the three sounds, with /ʃ/ backing to /x/ and /s/ fronting to /θ/.

  • Great answer! So you are saying this /x/ was the result of an internal development, entirely unrelated to Arabic influences?
    – Cerberus
    Oct 15, 2013 at 6:37
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    @Cerberus: Probably, yes. It's possible there was some Arabic influence but it seems unlikely because there are no Arabic borrowings in Spanish where Arabic /x/ or /ħ/ corresponds to Spanish /x/ (rather, it's Old Spanish /h/, no longer pronounced). Furthermore, the /x/ sound didn't develop until the mid-to-late 1500's, by which point there were basically no Arabic speakers left. Nov 6, 2013 at 3:38
  • OK very interesting.
    – Cerberus
    Nov 6, 2013 at 12:35
  • It’s worth noting that backing of /ʃ/ to /x/ is not typologically unheard of. The Swedish sje-sound (which is quite [x]-like in many dialects) primarily comes from /ʃ/, as do a lot of /x/’s in various Iranian and some Middle Indic languages. If memory serves, /ʃ/ became /x/ universally in Common Slavic (later refronted to /ʃ/ before front vowels). So it’s not really a development that is begging for an external trigger. Oct 30, 2020 at 21:59

Take into account that in old Spanish, the letter X had the phoneme /x/ like the original title of the famous book Don Quixote, and the country name we still pronounce with /x/, México.

I always thought this had to do with greek letter chi (X), because of the obvious correspondence in grapheme and phoneme, but that would require somehow a direct connection from Greek to Spanish without passing through Latin, which I'm not sure of.

On the other hand, influence from Arabic does seem a plausible explanation.

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    This is not exactly true. Cervantes wrote that work in Old Castilian (Old Spanish) where the letter <x> represented a voiceless postalveolar fricative, in other words /ʃ/. In English this is represented by the digraph "sh", so it's not the same sound you referred to.
    – Alenanno
    Feb 18, 2012 at 14:04
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    Yes, now it's "Don Quijote". By the way, it's not "somehow", I posted the 11 phases that attempt to explain how Spanish got the J from "K". The change related to your question is the step 10. :)
    – Alenanno
    Feb 19, 2012 at 0:15
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    @Petruza As I mentioned above, the phoneme /x/ in Spanish has two allophones: [x] and [χ], with the latter occurring naturally when /x/ precedes /o/ or /u/. This [χ] is a uvular fricative, not merely a velar fricative as the weaker [x] is. So Don Quijote is [d̪õ̞ŋkiˈχo̞t̪e̞], enjuto is [ẽ̞ɴˈχut̪o̞], and the Asturian city of Gijón has both sounds: [xiˈχõ(ŋ)]. I'm not sure whether both allophones occur in American Spanish or not, but the stronger [χ], which is a uvular fricative not a velar one, is quite prominent in Spain. The code point is U+03C7 GREEK SMALL LETTER CHI.
    – tchrist
    Feb 25, 2012 at 13:18
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    That's right, the stronger /x/ is more used in Spain, while it's softer in Latinamerica reaching in countries from central america nearly as soft as the english /h/.
    – Petruza
    Feb 26, 2012 at 4:16
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    Note that χ (the letter chi) was pronounced /kʰ/ in Ancient Greek, hence the Latin translitteration ch that we now use, which is /k/ + /h/ (the letter c was always /k/ in classical Latin).
    – Cerberus
    Feb 26, 2012 at 22:18

Its ironic that people think the |x| sound in Spanish is Arabic influence when it is precisely this sound which makes it so difficult to recognize the Arabic influence in Spanish lexicon.

The |x| sound comes from what Spanish speakers refer to as the readjustment of the sibilants which occurred over a rather short period shortly after the conquest of Mexico. Remember that the "x" sound in written Spanish used to refer to the "sh" sound which is the reason Mexico is written with an X. Early Spaniards referred to it as Meshico after the Meshica people.

The reason English speakers pronounce Don Quixote with a "sh" sound whereas Spaniards pronounce it with a |x| is because the English speakers are using the archaic Spanish pronounciation

Equally there are so many arabic words in Spanish which in Arabic are pronounced with a "sh" sound or an English/French "j" sound but were substituted for the Spanish J which sounds like a |x|.

Jaqueca (migraine) comes from the Arabic Shaqiqah. Jarabe (syrop) comes from the Arabic Sharab. Jeque comes from Sheikh. Ojala comes from the Arabic Law Sha Llah.

If it wasn't for this phonetic readjustment the Arabic influence in Spanish would be much more evident to Arabic speakers.

  • 1
    Do English-speakers say "Don Quixote" with [ʃ]? I've always heard it with [h] (something like [dɔŋ ki'how.tej]).
    – Draconis
    Oct 30, 2020 at 18:36
  • In UK and France they generally say it with a "sh" sound. In the US maybe they say it like modern Spanish.
    – Alex
    Nov 2, 2020 at 17:41

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