Difficulty in communicating may result from, among other factors, language- or terminological differences; lack of proficiency in the other language or register (for example, between speakers of different languages, or between experts in a given field and non-experts); cognitive gaps, i.e. unfamiliarity with certain concepts or processes (e.g. caused by insufficient access to education, low literacy, or cognitive development); lack of relevant information (e.g. about how to apply ); cultural differences (e.g. relating to concepts of politeness or punctuality); or disability (e.g. partial sightedness, hearing impairment). Thus mediation is a normal part of education, of most kinds of learning, and of life. While linguistic communication is the most useful, the most frequently used and most versatile means of mediation, non-linguistic elements such as pointing/gestures, using signs (e.g. on roads) and drawing may also be useful ways of mediating information.