What is the reason behind the expression "n'avoir qu'une"
Duoligo asked me to translate "Je n'ai qu'une photo dans mon album." Since I had never seen this expression before, I translated it as "I don't have a photo in my album.", because of the negation part "n'ai".
But it turns out, as far as I understood it, "n'avoir qu'une" + object means to have one of the said object. So in the sentence above, the correct translation is "I have one photo in my album" or "I only have one photo in my album." There is even an idiom for " N’avoir qu’une parole" which means "to keep one's words".
I'm not sure I get how the negation of the verb "avoir" translates into having something. Is it because of the "qu'une"? Does it convey a meaning like "he doesn't have it but one"?
"N'avoir qu'une" is a example of the "ne-verb-que" combination. It generaly means "only". Other examples:
- "Je ne joue qu'au baseball" : "I only play baseball"
- "Je ne mange que de la viande" : "I only eat meat"
- "Je ne marche que la nuit" : "I only walk at night"
Where the "que" is placed in the sentence change the meaning:
- "Je ne joue qu'au baseball la nuit" : "At night, I only play baseball"
- "Je ne joue au baseball que la nuit" : "I play baseball only at night"
"Je n'ai" alone does not mean none. "Je n'ai pas ...." is none. It's like I'm about to say I have none, then change my mind suddenly for dramatic effect and say I have "qu'un[e]" ... but one, reinforcing how very few photos I do have. So your assumption is correct. There is even an equivalent English idiom: "I have but one photo in my album." although the modern usage would be to say "I only have one photo in my album."