Answer by
LeheckaG (1826)
I doubt that your-parents are "tapping" your-cellular-telephone;
not that your-parents are not nosy/watchful.
The US-government has computers/analysts monitoring ALL "US-international"-calls for keywords.
Other than that,
it requires a court/judge-issued search-warrant to monitor/tap cellular/telephones.
Not that illegal/warrantless cellular/telephone-monitoring/taps are unheard of;
it takes a few-hundred-dollars of equipment to do so.