The normal PR (ie not via ARI) requires physical residency in the country (more than 183 days/year) for at least 5 years plus several other requirements, see https://imigrante.sef.pt/en/solicitar/residir/art80/. These requirements are consistent for all EU countries.
A2 is the language requirement.
For citizen applications, you may want to read the following:
Impressos e modelos | IRN.Justica.gov.pt). In Portugal, IRN is responsible for assessing applications for citizenship. The information is only in Portuguese. Right click, choose translate, for another language.
A Nomad poster has also provided a helpful long read here - a little further up on this thread.
Portuguese Citizenship application after 5 years of Golden Visa - #45 by susanayang
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