The development of pronominal indices on the verb and the development of subject-verb agreement are two sides of the same coin. This will be illustrated from the Latin-French history. The Latin verb has personal endings by which it agrees in person and number with its subject ().

If there is no subject, the finite verb can alone constitute a complete clause. Thus, omitting Iohannes from produces the meaning ‘he/she/it comes’.

French inherits this construction; from standard French is diachronically identical and synonymous with .

While the writing shows the third person singular ending, this is not reflected in the phonetics. In fact, the system of personal endings of the French verb is another example (besides the corresponding case in Portuguese) of almost complete grammaticalization to zero. All of the singular forms are homonymous.

French has a left-dislocation construction which, just as in other European languages, is well established in the colloquial language but essentially absent from the written standard. (It is not actually ungrammatical in the written variety, but just not considered good style.) is a variant of .

In this construction, the initial noun phrase is left-dislocated, thus not a constituent of the clause following it, and the resumptive pronoun il appearing in the latter is the subject of the verb and bears a normal anaphoric relation to the left-dislocated NP. As long as it is a left-dislocation construction, there is a possible pause after the left-dislocated constituent, and the anaphoric pronoun occupies that syntactic position which the left-dislocated constituent would occupy.

This construction is grammaticalized in colloquial French. has continuous intonation after the initial constituent.

The clause boundary between the initial constituent and the rest disappears and Jean becomes the subject of the verb. Il is reduced to a cross-reference index which occupies a fixed position in front of the verb and agrees with the subject. It thus fulfills the same function as the person ending -t fulfills in – without, of course, being diachronically identical with it. As an original personal pronoun reduces to a pronominal index, subject-verb agreement is renewed. is the colloquial counterpart to standard .