In your example:
Her dictionary said that tukio meant 'was'.
The word "tukio" needs to be in the same quotation marks as the word "was" is set in, such that:
Her dictionary said that 'tukio' meant 'was'.
Judging by your use of Punctuation, I'm going to guess you are using a British English writing guide as opposed to a North American ...
Rather than translating from UK to US English, I think a glossary would be a better idea. It would clarify things for non-UK readers, and also give them insight into our culture, just like we get insight into US culture.
I'm British and had to give up reading books on the Internet Archive because of this. Changing the spelling is one thing, but some publishers are so aggressive in their "translations" that the story no longer makes sense. They'll grudgingly leave in the fact that the story is set in London but that's it. One publisher claimed to love a certain ...