[2] EGŌ (nominative) MIHI (dative) MĒ (accusative) MĒCUM (ablative MĒ + CUM "with") yo (nominative) mí (prepositional) me (unstressed/clitic) conmigo (comitative) NŌS (nominative/accusative) NŌBĪS (dative/ablative) NŌBĪSCUM (ablative NŌBĪS + CUM "with") nosotros, nosotras (nominative/prepositional) nos (accusative/dative) connosco (comitative, archaic) TŪ (nominative) TIBI (dative) TĒ (accusative) TĒCUM (ablative TĒ + CUM "with") tú (nominative) ti (prepositional) te (accusative/dative) contigo (comitative) VŌS (nominative/accusative) VŌBĪS (dative/ablative) VŌBĪSCUM (ablative VŌBĪS + CUM "with") vosotros, vosotras (nominative/prepositional) os (accusative/dative) convosco (comitative, archaic) ILLE, ILLA, ILLUD (nominative) ILLĪ (dative) ILLUM, ILLAM, ILLUD (accusative) él, ella, ello (nominative/prepositional) le (dative), se (dative, alongside an accusative pronoun)[a] lo, la (accusative) ILLĪ, ILLAE (nominative) ILLĪS (dative) ILLŌS, ILLĀS (accusative) ellos, ellas (nominative/prepositional) les (dative) los, las (accusative) SIBI (dative) SĒ/SĒSĒ (accusative) SĒCUM (ablative SĒ + CUM "with") sí (prepositional) se (accusative/dative) consigo (comitative) Unstressed pronouns in Old Spanish were governed by rules different from those in modern Spanish.
[1] For example, from Cantar de Mio Cid: If the first stressed word of a clause was in the future or conditional tense, or if it was a compound verb made up of haber + a participle, then any unstressed pronoun was placed between the two elements of the compound verb[1] (this process still applies in European Portuguese where it is called mesoclisis).
For example: By the 15th century, Early Modern Spanish had developed "proclisis", in which an object's agreement markers come before the verb.
According to Andrés Enrique-Arias, this shift helped speed up language processing of complex morphological material in the verb's inflection (including time, manner, and aspect).
[3] This proclisis (ascenso de clítico) was a syntactic movement away from the idea that an object must follow the verb.
For example, in these two sentences with the same meaning:[4] "Lo" is the object of "comprar" in the first example, but Spanish allows that clitic to appear in a preverbal position of a syntagma that it dominates strictly, as in the second example.
When used together, clitic pronouns cluster in specific orders, and the process of enclitization is subject to certain rules in which sounds are dropped.
Enclitization is subject to the following rules: Non-clitic, or stressed pronouns, on the other hand, do not require a host, and they can thus be placed anywhere in the sentence.
Whether proclitic or enclitic, they cluster in the following order:[5][6] Thus: When an accusative third-person non-reflexive pronoun (lo, la, los, or las) is used with a dative pronoun that is understood to also be third-person non-reflexive (le or les), the dative pronoun is replaced by se: If se is being used as a reflexive indirect object, however, it is often, though not always, disambiguated with a sí: Only one accusative clitic can be used with a single verb, and the same is true for any one type of dative clitic.
It generally only occurs with: Thus: Accusative clitic doubling is also used in object-verb-subject (OVS) word order to signal topicalization.
The appropriate direct object pronoun is placed between the direct object and the verb, and thus in the sentence La carne la come el perro ("The dog eats the meat") there is no confusion about which is the subject of the sentence (el perro).