* No official census: There's no comprehensive census or survey in the UK that specifically asks about the languages spoken besides English.
* Definition of "English people": What defines an "English person" can be tricky. Do we include everyone born in England, or those who live there, or those who identify as English?
* Varying language proficiency: Even if someone speaks another language, their proficiency level could vary greatly. Do we count someone who understands a few basic phrases? Or only those who are fluent?
However, we can look at some relevant statistics:
* EU-wide data: A 2012 Eurostat survey found that 37.6% of people in England aged 16-64 spoke another language besides their native tongue. This number likely includes both native English speakers and immigrants.
* London as a multilingual hub: London is a very diverse city with a high proportion of residents speaking languages other than English. Studies have shown that over 50% of Londoners can speak another language.
In conclusion: It's safe to say that a significant portion of the English population speaks another language besides English, especially in London. However, providing an exact figure is impossible due to the lack of comprehensive data and varying definitions.