Wife not ready for more children

Q: I am married age 43 wife age 36 and son age 13 . I was suffering from Leucoderma, also known as vitiligo, is a rare skin disease characterized by white spots and patches. Alhamdulillah , it is cured and no one was aware about this. After marriage I had told her that once I was suffering this disease . When my son was 2 years old he also suffered from this desease. Alhamdulillah, my son is also cured. But my wife is not ready for more kids. She is fearing that our next child may also suffer from this disease. I told her several times that all disease/situations are from Allah Ta'ala and he is only who give us cure. But she is still not ready. In this situation , should I force her for more children? We are having normal relation of husband and wife or I can do second marriage for more kids or I should make sabr?

Speaking in languages other than Arabic

Q: What is the ruling on people who are capable of speaking Arabic, speaking in languages other than Arabic with one another? For example, `Ulama speaking in Urdu with one another, or English, instead of Arabic? I have come across certain narration from Hadhrat Umar ibn al-Khattaab رضي الله عنه as well as some other Sahaabah, in which they discouraged people from speaking in a language other than Arabic. There is also a Riwaayat which states that whosoever is capable of speaking in Arabic should not speak in non-Arabic for that causes Nifaaq. It is also mentioned that Imaam Ahmad ibn Hanbal رحمة الله عليه regarded it as Makrooh for a person to use non-Arabic words to describe the days and months, etc. Taking all of this into consideration, Mufti Saheb, what is the ruling on people learning and speaking languages such as Urdu, Gujarati, Farsi, English, etc. rather than Arabic? Is it permissible to do so? And if it is permissible, is there Karaahiyat in doing so?