In these contexts, the use of icons has many advantages: it makes no assumption about the language competences of the users, allowing impaired users, or users from a different linguistic background (which may not include a good command of one of the major languages involved in research on natural language processing), to access the systems; it may trigger a communication-motivated, implicit learning process, which helps the users to gradually improve their level of literacy in the target language.
icons suffer from a lack of expressive power to convey ideas, namely, the expression of abstract relations between concepts still requires the use of linguistic communication.