Articulation is the production of speech sounds that are created by movements of the articulators (lips, tongue, and jaw) and the vocal cords.
An articulation disorder is the mispronunciation of those sounds because of a weakness and/or a miscoordination between the muscles involved in the speech.
Children should be able to produce all speech sounds correctly by age 7. However, if an articulation disorder is present and not addressed, it may persist into adulthood.
The ultimate treatment is speech therapy and it focuses on teaching the difference between correct and incorrect productions. It also includes a rehabilitation of the weak muscles and the correct placement of the articulators and practicing the sound in words, sentences and ultimately, spontaneous speech.