O use of the singular and plural enclisis raises doubts related to grammatical facts. So, to support this discussion, let us observe the use of this modality in the following examples:
we send-them or we send-you
Appreciate-you
We deliver-you
We found that the verb forms appear accompanied, respectively, by the oblique pronouns “them/lo/you/te”.
In this way, such forms did not suffer any alteration, that is, because they belong to the first person plural (us), they appeared accompanied by the ending “-s” (we send, thank and deliver).
However, it is noteworthy that when it comes to grammatical exceptions, there is one of them that fits the subject in question, that is, if the verb form is first person plural and appears followed by the pronoun “nos”, it loses this ending (-s). Everything suggests that this position is due to issues related to euphony (relating to sound harmony), or even an ease of pronunciation on the part of the sender. So let's see the cases that represent such an exception:
we introduce ourselves
we complain
let us dedicate ourselves
Celso Cunha admits that such suppression is due to an old assimilation to the initial nasal of the following pronoun, as in the case of the examples mentioned above.
By Vânia Duarte
Graduated in Letters
Source: Brazil School - https://brasilescola.uol.com.br/gramatica/uso-enclise-no-singular-no-plural.htm