Can someone explain why "lo" is required in this sentence?

Question

Can someone please explain why lo is needed in this sentence? It confuses me and I can't find anything to explain it.

El calpulli lo formaban personas que estaban unidas familiarmente

Thanks.

Answer 1

If the sentence, as RubioRic rightly suggested, is:

• El calpulli lo formaban personas que estaban unidas familiarmente.

"lo" is an obligatory duplicate direct object. This occurs, among other cases, when the direct object is placed before the verb.

The normal word order is:

• Personas que estaban unidas familiarmente (I would have said "mediante/por lazos familiares") formaban el calpulli => Personas que estaban unidas familiarmente LO formaban.

Now, if the direct object "el calpulli" is placed before the verb, the rule transcribed below applies:

5.2. Si el complemento tónico no es un pronombre personal y aparece antepuesto al verbo, también es obligatoria la coaparición del pronombre átono, tanto si el complemento es directo como indirecto: A tu hermano lo vi en el cine (no *A tu hermano vi en el cine); La tarta la llevo yo (no *La tarta llevo yo); A mi madre le he dicho la verdad (no *A mi madre he dicho la verdad); A Juan le han denegado la beca (no *A Juan han denegado la beca). Deben diferenciarse estas construcciones, con el complemento tónico antepuesto y coaparición del pronombre átono, de aquellas en que la anteposición del complemento es enfática, contrastiva, en las que no coaparece el pronombre átono: Un libro te daré, y no dos (y no *Un libro te lo daré, y no dos).

According to this rule (Source), the direct object needs to be duplicated by means of the pronoun "lo" (or "la", "los", "las")

• La tarta la llevo yo (A variant of: Yo llevo la tarta).

• El calpulli lo formaban esas personas (A variant of: Esas personas formaban el calpulli).

It is worth stressing that the original sentence "El calpulli lo formaban ..." flows much better than "Personas ... formaban el calpulli" because the subject "Personas ..." is too long and is indeterminate, so its initial position would sound unnatural.

Note: As stated by DPD under 5.2. above, when contrast needs to be expressed the duplication of the direct object does not take place. One important detail is omitted there, and that is that the preposed object is usually unspecified. The example provided there is:

• Un libro te daré, y no dos. (contrastive structure)

Here follow some more examples to prove the point of this note:

• El libro te lo presto, pero la revista no. (contrastive structure with specified object: duplication)
• Leche compré, pero yogurt no. (contrastive structure with unspecified object: no duplication)
• La leche la tomo, pero el yogurt no. (contrastive structure with specified object: duplication)

Sometimes indetermination is conveyed by the plural form:

• Consejos vendo, pero para mí no tengo. (unspecified object: no duplication)
• Malas noticias me traes. (unspecified object: no duplication)