Teach a man to fish time! I can show you how to solve these interesting Ngram mysteries for yourself.

1. See a curious peak.
2. At the bottom, look at the date range searches, click the closest one to the peak.
3. Using the advanced search function at the top, adjust the date range to closer match your peak if needed.
4. Open the books and look at the context of where this word has been found by the keyword search.

For example, "iphone" is mostly OCR transcription errors - Some of them are from the word "Ediphone," others are "1 phone." And some other stuff like that.