Here's why it's difficult to determine:
* Limited data: The US Census didn't include questions about language spoken at home until 1980.
* Shifting demographics: The US has a diverse population with a constantly changing linguistic landscape.
* Immigrant populations: Large immigrant populations were arriving in the US throughout the 20th century, bringing their native languages with them.
Possible contenders for the second most spoken language in 1960:
* Spanish: Given the large Hispanic population in the US, Spanish is a strong contender for the second most spoken language, even in 1960.
* German: German was historically a significant immigrant language in the US, though its prevalence declined throughout the 20th century.
* French: French, especially in areas with historical French settlements, could have been a significant language.
* Italian: Italian was also a major immigrant language in the US, with a strong presence in some regions.
Without specific data from 1960, it's impossible to definitively name the second most spoken language.