Speaking and listening is the bedrock of learning. It is the first stage of learning and if it not completed then the learner will have deficiencies later in their academic and lives.
It is better to say listening and then speaking in my opinion as listening happens before speaking. The one who did not listen sufficiently cannot speak correctly because humans learn by examples. Examples of them interacting with people who have had more exposure to language.
By language, I mean quality language.
It is because of this Harrow Tutorial have devised Listening and Speaking courses to help bridge these gaps.