Adjectives and adverbs are words that describe or modify other words.
http://www.bbc.co.uk/learningenglish/english/course/intermediate/unit-8/session-2/activity-3
Linking devices are used to link one idea or argument to another. A common situation is when we are talking about something that happens and its result, or a cause and its effect.
http://www.bbc.co.uk/learningenglish/english/course/intermediate/unit-10/session-2/activity-3