The theory of love languages was first expressed by Gary Chapman in his book titled The Five Love Languages: How to Express Heartfelt Commitment to Your Mate.

According to the book, there are five ways to express and experience love that Chapman calls "love languages";

1. Receiving gifts
2. Quality time
3. Words of affirmation
4. Acts of service (devotion)
5. Physical touch

According to this theory, each person has one primary and one secondary love language.

Chapman suggests that to discover another person's love language, one must observe the way they express love to others, and analyze what they complain about most often and what they request from their significant other most often. 

He theorizes that people tend to naturally give love in the way that they prefer to receive love, and better communication between couples can be accomplished when one can demonstrate caring to the other person in the love language the recipient understands. 

An example would be if a husband's love language is acts of service, he may be confused when he does the laundry for his wife and she doesn't perceive that as an act of love, viewing it as simply performing household duties, because the love language she comprehends is words of affirmation (verbal affirmation that he loves her). She may try to use what she values, words of affirmation, to express her love to him, which he would not value as much as she does. If she understands his love language and mows the lawn for him, he perceives it in his love language as an act of expressing her love for him; likewise, if he tells her he loves her, she values that as an act of love.

Status of this theory

There has been a lack of research to test the validity of Chapman's model and whether it can be generalized. Egbert (2006) suggests that the Five Love Languages might have some degree of psychometric validity despite its abstract nature.

Applicability

Whether there is any legitimate scientific foundation for this theory, it has immense practical application in relationships. In particular;

• Learning how others "experience love" (which could be thought of as Oxytocin or Serotonin triggers), and being able to communicate to them in that language.
• Understanding what you need from your partner.
• Strengthening important relationships, whether romantic, friendship, or family.

Relationship with Yourself

BROJO's Coach Mike applies the theory more broadly, to include one's relationship with themselves. Showing yourself self-appreciation means expressing those same love languages to yourself (and avoiding their opposites).

For example, if Words of Affirmation are important to you, then being overly critical of yourself will likely cause a sense of self-doubt and self-loathing. Likewise those who value Physical Touch will likely benefit on an emotional level from more kinesthetic activities - gym, yoga, dance, & massage therapy as examples.

Gift-giving

Coach Mike also applies the 5 love languages in gift-giving. Often we think of gift-giving as either being the gift of a thing, or a compliment. That can be well expanded along all 5 of the love languages;

1. Material gifts, anything from buying someone lunch to giving them a single flower, or even a paper flower.
2. Words of affirmation - verbal or written compliments.
3. Quality time, giving someone your time and attention alone.
4. Acts of service - do something for someone. Simple things like helping them put their coat on.
5. Physical touch must be used very carefully - particularly across gender lines - however even simple gestures such as standing close to someone, a warm handshake, or a pat on the back, can be very powerful ways of expressing trust and appreciation towards someone.

Further reading

The Five Love Languages ( Wikipedia )

Learn to Speak Your Partner's Love Languages ( The Gottman Institute )