Passive voice and other tenses
"Se dicen" is "one says," "they say," "it is said."
Does this generally change tense/aspect? My examples may not be perfect examples, so let's not leave the question to correct them overmuch if they're not ;)
"It used to be said that women could not..."="Se dicían que mujeres no pueden..."?
"If that's how they say it in Mexico"="Si se digan en México"?
"One would say José is handsome"="Se dirían que José es guapo."?
Or are any of these just "se dicen"?
[That is not passive voice, it is only sentences in active voice (?) where subject is impersonal].
This type of sentece doesn't have plural, it is always "se dice"/"se decía", never "se dicen" (that means "they say themselves" or "they say each other"). They change tense or aspect, but not number and I suppose they always are in Indicative mood.
1- "Se decía / solía decirse que las mujeres no pueden... (i.e.: fly) / no podían... (i.e.: drive a car)".
2- "Si así es como se dice en México"
3- "Se diría que José es guapo".
I was surprised to hear about the passive voice, but I see you're right! "Finally, we use “se” constructions with non-personal subjects. While it’s often translated to the passive voice in English, “se” constructions are not considered passive voice in Spanish." https://www.fluentu.com/blog/spanish/spanish-passive-voice/
Oh, yes. English has passive voice for those senteces. In Spanish, passive voice is made in the same way: "to be + participle": I am known as Batman = Soy conocido como Batman.
If I remember correctly, those non-personal sentences are in a so called "voz medio-pasiva" (middle-passive voice) used also for "Se venden casas" (~ Houses are sold) or "Se prohibe fumar" (~ Smoking is forbidden)
"Voz medio-pasiva" definitely rings a bell from somewhere. Hard to imagine where else but here, then!
Dicían, indicative imperfect past tense (used to)
Digan, subjunctive present tense ( expresses uncertainty) if
Dirian, indicative conditional tense ( would, could, should) any verb with , examples, "ría" as part of the verb extension expresses conditional....ex: dirian, podria, Comeria, hablaria, tomaría, etc ...
Se dice/dicen que, yes, I take it to be , present tense, "he/she/it/They say.....
*"Decían". But it is impossible to say "se decían" for this type of sentences.