A love language might sound like a concept from teen fiction but in fact it comes from a 1995 non-fiction book by Gary Chapman. The Five Love Languages: How to Express Heartfelt Commitment to Your Mate was a popular book on relationships at the time and while it may be somewhat arbitrary in the advice it offers (as with many such books), it nevertheless raises an interesting idea that may be applicable still to many relationships today.
The general idea behind the 'Five Love Languages' is that we each have a preferred means of expressing our love and that these generally fall into five (convenient) categories. These are:
Words of Affirmation
Acts of Service
So for instance, someone you know may express love for their partner by showering them with gifts, where as someone else might express their affection by telling them how much they mean to them. Yet another person might express themselves best through physical touch and various forms of intimacy.
As mentioned, this whole idea is somewhat arbitrary. Most of us will in fact have multiple ways that we express ourselves and in all likelihood there are many more methods than just these five.
Applying the Theory to Your Relationship
But while this idea may fall very much into the 'pop psychology' category, it nevertheless still has its uses and raises some interesting ideas.
For instance, it certainly is true that we each express ourselves differently and it's easy for us to overlook how this might be perceived by our partners. If your partner is someone who grew up in a family that dished out lots of praise and lots of hugs but you tend to express yourself through acts of service (putting up the shelves or doing the washing for instance), then there's a good chance that you may inadvertently be leading them to feel underappreciated.
On the other hand, if you are currently feeling underappreciated by your partner, then perhaps consider some of the other ways in which they may be showing their appreciation. Perhaps they are doing a lot for you that you have overlooked but it's just not in the format that you're used to.
The best way to ensure that both of you feel fulfilled and appreciated though? That's to ensure that you are expressing yourself through as many love languages as possible. This will bring more dimensions to your relationship and ensure that you both feel completely secure in the knowledge that you are appreciated and loved.