Where does “มอนทรีออล” come from?

มอนทรีออล (Thai) comes from English Montreal, from French Montréal, from Middle French Montreal, from Middle French real, from Old French reel, from Latin reālis, from Latin rēs, from Latin vindicatio — shoe.

Ancestry of “มอนทรีออล”, step by step

Step	Language	Word	Meaning
1	English	Montreal	Quebec
2	French	Montréal	—
3	Middle French	Montreal	at its confluence with the Ottawa River
4	Middle French	real	royal; Alternative form of royal
5	Old French	reel	—
6	Latin	reālis	real
7	Latin	rēs	thing, object, stuff
8	Latin	vindicatio	civil lawsuit; protection, defence; vindication;...
9	Latin	vindicō	to lay claim to as one's own (often with sibi)
10	Latin	vindex	claimant, vindicator
11	Latin	dīcō	to say, talk, speak, utter, mention
12	Latin	-tiō	tion, -ation, -ing
13	Latin	dissertātiō	(spoken) dissertation, discourse, disquisition
14	Latin	dissertus	arranged, disposed; explained
15	Latin	disserere	second-person singular future passive indicative...
16	Latin	dis-	asunder, apart, in two; reversal, removal;...
17	Latin	calceus	shoe

Every word from Latin calceus →Every word from Latin -tiō →Every word from Latin dis- →