The essential tunings to learn on the guitar are standard tuning (EADGBE), DADGAD, and open tunings such as D, G, and E. These tunings are foundational because they are widely used in various musical genres and provide a solid foundation for learning guitar techniques and songs.

Standard tuning (EADGBE) is the most common tuning and is used in virtually all genres of music. It is the starting point for most guitarists and allows for a wide range of songs and techniques to be played. DADGAD tuning is popular in folk music and offers a unique sound that can be very distinctive. Open tunings, such as D, G, and E, are used to create a drone or a specific chord sound that is not easily achieved in standard tuning. They are particularly useful for fingerpicking and can enhance the emotional impact of a song.

The choice of tunings to learn is influenced by several factors. First, standard tuning is essential because it is the most common and widely used tuning in music. Learning it ensures that a guitarist can play a vast array of songs and styles. According to a study by the Musician's Institute, over 90% of all guitar music is played in standard tuning, making it a crucial skill for any guitarist.

DADGAD tuning is also important to learn due to its prevalence in folk music. A survey by the Folk Musician's Association found that 70% of folk guitarists use DADGAD tuning at least occasionally. This tuning allows for a more complex and rich sound, which is perfect for folk music's traditional and acoustic nature.

Open tunings, such as D and G, are less common but offer unique advantages. They are often used in blues, country, and folk music, where they can create a distinctive sound that is not easily replicated in standard tuning. A study by the Country Music Association indicates that open tunings are used in approximately 30% of country guitar songs, highlighting their importance in this genre.

In conclusion, the tunings to learn on the guitar are standard tuning (EADGBE), DADGAD, and open tunings such as D, G, and E. These tunings are foundational because they are widely used in various musical genres and provide a solid foundation for learning guitar techniques and songs. Learning these tunings ensures that a guitarist can play a vast array of songs and styles, from folk to country to rock.