Translation:We have been finding children that do not know how to read.
Portuguese "present perfect" (which is not a present perfect, but a "pretérito perfeito composto"), although having the same "structure", doesn't have the same meaning as the "present perfect".
It certainly carries a "repetition/continuity" meaning and is never used for a single, non continous, action.
- A gente tem encontrado = We have been finding
- A gente encontrou = we have found
Of course, the presence of adverbs and better context may change that.
- I have found a cat under the car = Eu encontrei um gato embaixo do carro
- I have been finding coins around = Eu tenho encontrado moedas por aí
Not really: "We have found" is the more formal literary form, which would be used in, say, a written statement by a researcher about the finding. So both would mean the same thing. Continuous belongs more to the spoken and informal language. Both refer to occurrences in a period of time from a point in the past (when the observations began) and now.
"We found" would refer to a specific time or period wholly in the past. e.g. "Last year in our survey, we found (or were finding) children who could not read." but "In our current study, we have found . . . "
Present Perfect is not more literary than PPProgressive. We use Present Perfect (1) when we want to talk about the number of times something happened in the past (without specifying the exact time) that impacts the present,(2) when we use the adverbials "ever"and "never", (3) for static verbs that can't be used as progressive form (4) and when something has just occurred and, as in all the other situations, impacts the present.
PPP functions to express the idea of something that starts in the past and continues up to this very moment or has just finished but whose effect is still in evidence. **
** The rain STOPPED an hour ago (but you can still see the puddles on the street.)
You would say: "It's been raining." You wouldn't say: "It has rained."
I've taught these tenses in France, Brazil and to foreign students in the US - which is why these rules are forever burned in my memory.
I am still an absolute beginner but I think that Duo is correct here. Tenho falado muito = I have been speaking a lot and NOT I have spoken a lot. The perfect tense expresses an action started in the past and continuing almost up to the present. It is formed with the present indicative of the auxiliary verb ter (or less commonly haver) and the past participle of the main verb. E por causo disto 'tem encontrado' = 'Have been finding'. But no doubt Ceaer or Davu or PaulEnrique or ChrisBoc will correct my explanation.
Pezbabel, I believe the reason your sentence is not accepted is because "We have found children who can't read" would make it be past tense, while this is continuous. "We have been finding children who cannot read" is a continuous, and ongoing, not a one time thing. The meaning would convey that there perhaps are more who still cannot read.