If I write the name of Allaah in English, do I have to use a capital 'A' for the name of Allaah? When I write Allaah with small 'a',​ I have no intention of disrespecting my Lord, Allaah; am I doing anything wrong? Also, are there names of the days used by the Muslims? Does it matter what names we use, whether it be in English or not? I try not to utter the names of the days in English because of the origin of these words. What are the names of the days used by the Muslims, and should we use them?

All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

It is not forbidden for you to write Allah with a small 'a', and there is no religious impediment to this.

As for the names of the days used by the Muslims, they are the names known in the Arabic language. There is no religious impediment to using the English names even if they carry meanings that do not conform to the Shariah. This comes under the heading of informing, not giving a name.

Ibn Al-Qayyim wrote:

"As for his saying, 'I am the son of ‘Abdul-Muttalib,' this is not intended to approve the use of this name, rather he (the Prophet) was simply informing of the name by which that person (his uncle) was known. Using a name to make known who is being spoken about is not prohibited, and saying that this is an exemption for the name of ‘Abd Al-Muttalib, as Abu Muhammad ibn Hazm said, has no basis, as the Companions also called the tribes of Banu ‘Abd Shams and Banu ‘Abd Ad-Daar by their names, and the Prophet, sallallahu ‘alayhi wa sallam, did not forbid it or denounce them for that. Informing of a name is broader than giving a name; what is permissible in the former is not permissible in the latter." [Tuhfat Al-Mawdood bi-Ahkaam Al-Mawlood]

We advise you to beware of Waswasah (obsessive doubts) and indulgence in asking questions about such matters; verily, this leads to evil consequences.

Allah knows best.