What is the diffence between "to fight with sb" and "to fight sb" Hello! Now I'm reading a book about history of London in English. 
There are 2 sentences. "The Romans started a fight with the wrong person" and "His men fought the people". 
Please teach me when I should use "to fight with sb" and "to fight sb". Thank you. 
May 2, 2019 4:17 PM
Comments · 5
Hi Alexandra!
I'm a Vietnamese. As I know, " to fight with sb" means to have an arguement with sb about st and " to fight sb" means to take part in a war against an enemy. 
I hope my explaination will be useful to you!
May 2, 2019

The ambiguity is resolved by native English speakers by turning fight into a verb and then declaring who they are either fighting with or against, or sometimes both. Often the context makes it clear or clearer. 

"he/she/they/the Russian army/people etc are fighting with the Poles against the vietnamese"  

"Mr Smith is fighting Mrs Smith again" reasonable to assume it is a family dispute but it might not be.

"Mr Smith is fighting with Mrs Smith" from the context it is reasonable to assume it is possibly a family dispute but it may not be

"Mr and Mrs Smith are fighting together In the army" which army and if they are actually together in the same unit or war zone we do not know. 

"Mr Jones has gone of to fight with the Belgian Army" ambiguous 

"Mr jones has gone of to fight IN the Belgian Army" is how we specify as part of an army or group. 

"Mr Daniels is Fighting the neighbours" 

"started a fight with" at least in BR English the word started would be understood as meaning began to fight against somebody or a group of people. 

May 3, 2019
Good question! I thought I'd know the answer, but I'm going to give you a link to a webpage that explores it:  <a href=""></a>;
May 3, 2019
Ngoc is absolutely correct. That said, in your example, Alexandra, there is a simpler explanation: When the word “fight” is a noun, it is usually followed by the preposition “with” or “against” if we want to introduce the person(s) (whom) one is fighting. (“With” is ambiguous — it could possibly indicate you are fighting on the same side). Perhaps in Russian, no preposition is needed, but English has no declensions for case, so we need a preposition.

May 3, 2019
Thank you. 
May 3, 2019