English has two unrelated -ing suffixes

Surprising etymology fact:
The “-ing” suffix in phrases like “I like running” is etymological unrelated to the “-ing” suffix in phrases like “I am running”.
“-ing” is actuall two unrelated suffixes in English, spelled the same.

Quick grammar background:
Gerunds are nouns that are made from verbs, formed by adding “-ing”, e.g. in sentences like “Reading is fun”, “I enjoy digging”, “Living underground is safer”.

The present participle is a form of verb that uses -ing to show the action is continuous, like in “The pancakes are burning”, “I am burrowing”, or “We are starting a new life underground”.

These -ing suffixes are so similar that they can be easily confused, but their origins are entirely separate, and until a few centuries ago they were spelled differently in English.