I think he was referring to the students difficulty in "expressing" themselves in code. In the same fashion non-native speakers have a hard time expressing idea

I think he was referring to the students difficulty in "expressing" themselves in code. In the same fashion non-native speakers have a hard time expressing ideas in a foreign language. For example, I know I want to ask for another beer but composing the sentence along with all the right grammars is hard for me in Spanish. Similarly, to a novice programmer she may know she wants a loop but writing out the correct syntax is simply difficult for her.