"Outside speech, the association that is made in the memory between words having something in common creates different groups, series, families, within which very diverse relations obtain but belonging to a single category: these are associative relations"

This quote by Ferdinand De Saussure is describing the idea of associative relations in language. He is recommending that when we hear a word, it can bring to mind a series of various other words that belong to it somehow. These words can be connected to each various other in a variety of means, but they all come from the exact same classification. For example, when we hear words 'feline', we may think of other pets such as 'canine', 'mouse', or 'bunny'. We may likewise think about associated concepts such as 'pet dog', 'fur', or 'meow'. Every one of these words belong to the word 'feline', yet they are related in various means. This is what De Saussure is describing when he talks about associative relations. He is suggesting that when we hear a word, it can bring to mind a variety of various other words that relate to it somehow, as well as these words can be organized together in a solitary classification.