What does からか mean?


I'm translating the following sentence from a book (exact sentence is directly
after dialogue in the picture).

> 興奮 **からか** 銀髪の外国人の口調は、いつになく流暢だった。

I have absolutely zero clue what "からか" means in general and in the context of
the above sentence, as I've never encountered it before in my Japanese classes
(I know what "から" and the sentence-ending "か" mean, but not this). Can someone
explain what it means?

Edit: Based on Ringil's answer, would the following be a possible, accurate
translation while taking the からか into account?

> "The doubtful interest in the silver-haired foreigner’s voice was unusually
> fluent."

[![](https://i.stack.imgur.com/Pfqky.jpg)](https://i.stack.imgur.com/Pfqky.jpg)




You should think of this like から+か. If there wasn't a か, the following would
just be a statement of a fact. The から is used to give the reason for the
unusual fluency of the foreigner (in this case it is because the foreigner was
excited/agitated).

> 興奮から銀髪の外国人の口調は、いつになく流暢だった。

With the か, the speaker is no longer certain for the reason. The speaker is
now only speculating that the reason for the unusual fluency was because the
foreigner was excited/agitated. The か indicates speculation/doubt. You might
have seen a phrase like 本当かどうか before. It's the same idea.

EDIT: If you want an accurate translation you could say something like

> The silver-haired foreigner was speaking unusually fluently. Perhaps it was
> because he/she was excited.




> (I know what "から" and the sentence-ending "か" mean, but not this)

Yes, it's this から followed by this か. から here is a reason/cause marker. か is a
question marker but is used like "presumably" or "probably" here. And 興奮 is
"excitement", not "doubtful interest".

  * 興奮: excitement
  * 興奮から: due to his excitement, ...
  * 興奮からか: presumably due to his excitement, ...; maybe he was excited, so...

This type of か meaning "presumably" can be used with a few other particles and
a te-form. Examples:

> 私がベジタリアンであることを知らずに **か** 、彼は肉料理の話をしている。  
>  Presumably not knowing I am a vegetarian, he is talking about meat dishes.
>
> 昨日の口論のせいで **か** 、彼女は学校を休んだ。  
>  Probably because of the yesterday's argument, she was absent from school.
>
> 私が溜息をつくのを見て **か** 、彼女は私に声をかけてきた。  
>  Perhaps she saw me sigh; she came and spoke to me.

