Is this a recent experience? I've found the voice search to be incredibly proficient recently. It's slightly embarrassing, but I use it for search and text dictation almost constantly.
Sometimes Google thinks I'm speaking German when really I'm speaking English and vice versa (especially searching for English named products with a German phrase).
It can get really annoying sometimes. But I guess it's mostly my fault for falling out of the default modus operandi. :)
She hates most technology and just likes her old and tried ways and it has shocked me how much she picked up voice search and texting.
This only applies to generic language. Unusual phrasings, niche words, or proper nouns come out wrong. This make speech perfect for quick texting, but still unusable for real writing.