Analfabeta vs. illetterato
The Italian words analfabeta and illetterato both refer to a lack of literacy, but they have distinct nuances in their meanings and usage.
Analfabeta
B1Analfabeta specifically refers to someone who cannot read or write at all. It indicates a complete lack of basic literacy skills.
Mio nonno era analfabeta perché non ha mai avuto l'opportunità di andare a scuola.
(My grandfather was illiterate because he never had the opportunity to go to school.)
In alcuni paesi, il tasso di analfabeti è ancora molto alto.
(In some countries, the rate of illiterates is still very high.)
Illetterato
B2Illetterato has a broader meaning. It can refer to someone who is uneducated or uncultured, not necessarily completely unable to read or write, but lacking in formal education or literary knowledge.
Anche se sa leggere e scrivere, è considerato illetterato perché non ha mai letto un libro.
(Even though he can read and write, he's considered illiterate because he has never read a book.)
Il nuovo capo è illetterato in materia di tecnologia.
(The new boss is illiterate when it comes to technology.)
Summary
While analfabeta strictly refers to the inability to read and write, illetterato has a broader meaning that encompasses a lack of education or cultural knowledge. Analfabeta is used for complete illiteracy, whereas illetterato can describe someone with basic literacy skills but limited education or expertise in a specific area.