If you didn't already know, the love languages aren't based on science but instead observations made by a Baptist pastor.
Acts of service, physical touch, quality time, gifts, and words of affirmation might sound nice, but there's no scientific evidence to say people prefer to give and receive love in one of these five ways.
The book, The Five Love Languages: The Secret to Love that Lasts, was first published by evangelical Christian Gary Chapman in the early '90s, and is based on trends he saw in couples he was counselling through the church.
Since its release, just a handful of studies into the theory have been conducted, and according to Gery Karantzas, a professor in relationship science at Deakin University, the research leans more towards refuting it.
"A lot of people assumed [the author of The Five Love Languages] was a psychologist or relationship expert, on which they can provide advice and that advice is well founded," Dr Karantzas says.
"People are surprised to find out that's not the case."
The book has been criticised for its lacking credibility, with psychologists including Dr Julie Gottman (co-founder of The Gottman Institute) labelling the theory as "superficial and rigid".
And yet the five love languages have become a popular cultural norm, and for many, a basis for trying to better understand their relationship dynamic.
But should we really be navigating the often murky waters of romance with a concept developed on speculation guiding the way?
The pastor behind the love languages
US-based Dr Chapman, who has a PhD in adult education, claims that everybody has a primary love language and says learning to speak the language of your partner is the key to a happy relationship.
It's obviously an appealing idea, with his book selling 20 million copies.
Dr Chapman has previously been asked about the book's lack of academic underpinnings, to which he replied: "Most people are not going to read an academic book on marriage. The normal person wants to know 'What's going to help me?'"
The 85-year-old's theory hasn't just been slammed for being pseudo-science, but also for its heteronormativity and sexism.
Feminist writer Zawn Villines, for example, called it "unscientific bullshit" that has been "weaponised against women demanding more from their relationships".
A helpful or harmful communication tool?
Dr Karantzas, who is also a certified couples therapist, says using the love languages as a way to unpack our relationships could be a problem.
He says people only seeing their partner through a particular lens "complicates things".
"You are likely missing, and ignoring, the many ways we tend to try and communicate in a relationship," he says.
"Often those blind spots are the places where the action needs to occur."
He says what we do have an "abundance of evidence for", however, is that an ability to read what our partner needs and respond in a way that meets those needs "is critical".
"It applies to parent-child relationships, and romantic relationships.
"But the ability to do that well is very hard."
Dr Karantzas doesn't use the love languages in his practice, but acknowledges there are clients who come to him talking about it.
"If it provides a way to establish rapport and have a language to start talking to a couple about their similarities and differences, you can go there as a starting point," he says.
"From there you jump off into the evidence-based therapies and approaches that we know are effective in making things work."
Psychologist and couples therapist Sian Khuman treats Dr Chapman's theory the same way.
If volunteered by clients, she will "use it as a discussion point to look at how each person in the couple experiences love, and make it a much deeper conversation about love and connection".
But there are those who include the theory in their work with couples.
For example, on its website Relationships Australia Queensland cites it as "a way for us to connect with our partners and create long lasting, happy and stable relationships".
Alex from Melbourne took the love language quiz after it was recommended to her by a relationship counsellor.
The 30-year-old says it was a helpful "communication tool" for prompting conversation with her husband about showing appreciation for one another.
But discovering the concept is based on anecdotal evidence only is a hard pill to swallow for the engineer who says she has a "very scientific mind".
"My first reaction was shock that professionals are using this," she says.
"When something is so prolific in society, and professional counsellor is vouching for it, I just assume it has scientific backing.
"I need to stop that and do my own research — which is what I do with a lot of things in life."
Should we abandon the love languages?
Dr Karantzas says if you've found the love languages work for you, then stick to it.
"But I would say buyer beware, because there are times it will get them into a pickle and they won't know why."
He says it's better to focus on understanding your partner, without trying to pigeon-hole them.
"Just do the best you can to tune into your partner's needs — that's not about the way they talk about love, or you talk about love, it's about you understanding your partner, and you don't need a love language to do that."
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