A bilingual app is not an English app with the words swapped out. When Arabic is a first-class language in a product, it changes layout, typography, numerals and tone — and users feel the difference immediately.
Direction is the obvious one: the whole interface mirrors for right-to-left. Navigation, icons, progress bars and animations all flip. But the subtle work is everywhere else. Arabic text needs more vertical line-height to breathe, and a typeface chosen for legibility on screen — not a Latin font with Arabic bolted on. Mixed content (an Arabic sentence with an English brand name or a phone number) has to keep each fragment in its correct direction without breaking the line.
Numerals are a real decision, not a default. Eastern Arabic numerals or Western digits? Currency, dates and phone numbers each have a convention users expect, and getting it wrong makes a screen feel foreign.
Then there is tone. Good Arabic copy is not a literal translation of the English; it is written natively, so it reads as if the product was born in Arabic. The same applies in reverse.
We build both languages in parallel from day one rather than bolting the second one on at the end. It is the only way the app feels native in each — instead of correct in one and translated in the other.