One of the current principles for language educators is that the four skills should be integrated as much as possible.  This will be a key guideline when we discuss unit planning in full detail (which will in the Curriculum Design course in the spring semester).  In the meantime, the posts here will be at least two-dimensional: that if students are to speak or write, we much know what they will do first (which might be to listen to or read something); and if students are to listen or read, we must include what they will do next, which will often involve speaking or writing.  The formulae are very simple:

X + Speak/Write;  Listen/read + Y.

Here are some simple examples: (1) in a common Co-operative Learning task called Think-Pair-Share, students in the early days of a new course might be directed to think of three specific L2 skills they want to develop through participating in this class (they may make notes if they wish); they then tell their partner (THINK + SPEAK); their partner listens carefully and passes the ideas to the rest of the group (LISTEN + SPEAK).  (2) The teacher removes  the title from a reading text; students skim the text and then work in pairs to write a good title (READ + SPEAK; DISCUSS + WRITE).  They then see the original title and must explain why their title is just as good (READ + SPEAK).  (3) Students study a graph or table of information and then write a paragraph summarizing the key information (PROCESS DATA + WRITE).

In other words, as we collect tasks and procedures related to particular skills, the specific skill will never be a single, free pedagogical molecule, but always linked to at least one other element.