Salam Miriam, We don't have a letter in Arabic to match the English "g"! Therefore, some would replace the "g" with ج or ك or غ! Personally I replace the English "g" with ج, because this is how I was taught, yet my way isn't the only way, because maybe other native Arabic speakers in Morocco let's say, were taught to replace it with ك. So I believe there's no standard way to write إنجليزي/ اللغة الإنجليزية.

The equivalent to the "G" is the letter "ج". In classical Arabic (Fusha), it's a soft "G", rather than a hard "G" sound. So there might have been a need to replace it with another letter, in this case a "ك" (although I have no idea why this one was chosen) . However, in many dialects, the "ج" sound is actually a hard "G". so it's written with a "ج". I think you should always type " الإنجليزية " regardless.

اللغة الإنجليزية حصة إنجليزي انكليزي تبدو غير صحيحة تبدو*

اللغة الإنجليزية إنجليزي

عموما على كيفك، لكني افضّل ان اكتب انجليزي