Is it permissible or forbidden to contact a non-mahram woman via Facebook for the purpose of learning French?

The general rule is that it is permissible for a woman to teach men and for a man to teach women, provided that the Islamic guidelines are observed, such as hijab, absence of forbidden mixing and khalwa (private seclusion), and that the speech is appropriate without coquetry or softness in tone, because a woman's voice is not awrah (nakedness) in itself.

The scholars of the Permanent Committee (for Islamic Research and Fatawa) said: "A woman's voice itself is not awrah. Listening to it is not forbidden unless it involves breaking in speech and softness in tone, in which case it is forbidden for her to do so to anyone other than her husband, and it is forbidden for men, other than her husband, to listen to it; due to the Almighty's saying: (O wives of the Prophet, you are not like any other women. If you fear Allah, then do not be soft in speech [to men], lest he in whose heart is disease should covet, but speak with appropriate speech)."

Nevertheless, prevention is better than cure. Islamic law has forbidden women from leading men in prayer, giving the call to prayer (adhan), and delivering the Friday sermon, as a means of blocking pretexts (sadd al-dhari'ah) and closing the door to temptation (fitna), and to protect her and those who listen to her, especially since hearts in these times are weak. Private correspondence with a woman contains a type of seclusion with her through conversation, and prolonged engagement in this is a dangerous door leading to attachment and infatuation.