According to new research simple words such as 'be', 'that', 'will', 'him', 'and' and even 'a' could hold the key to a successful marriage.
Experts say the style in which couples talk and how they use common words can predict whether a relationship will be successful or not.
It is already well known that people are attracted to potential partners who resemble themselves in personality, values and physical appearance.
However, experts now claim these features only skim the surface of what makes a relationship work.
The ways that people talk are also important according to the study which found that people who speak in a similar style are more compatible. The US study focused on what it dubbed 'function words'.
These are not nouns or verbs, but everyday words such as a, be, anything, that, will, him and even and. Study co-author Professor James Pennebaker, of Texas University, said how we use these words constitutes our writing and speaking style and couples who use them in the same way have better and longer-lasting partnerships.
Researchers examined whether the speaking and writing styles couples adopt during conversation with each other predict future dating behaviour and the long-term strength of relationships.
They conducted two experiments in which a computer programme compared partners' language styles.
In the first study, pairs of college students had four-minute speed dates while their conversations were recorded. Almost every pair covered the same topics, such as their study subject, where they were from and if they liked college.
Prof Pennebaker said: "Every conversation sounded more or less the same to the naked ear, but text analysis revealed stark differences in language synchrony. The pairs whose language style matching scores were above average were almost four times as likely to want future contact as pairs whose speaking styles were out of sync."
A second study revealed the same pattern in everyday online chats between dating couples over the course of 10 days. Almost 80 percent of the couples whose writing style matched were still dating three months later, compared with approximately 54 percent of the couples who did not match as well.
Prof Pennebaker said: "What people are saying to each other is important, but how they are saying it may be even more telling.
"But what's wonderful about this is we don't really make that decision - it just comes out of our mouths. People are not consciously synchronizing their speech."
The article appeared in the journal Psychological Science.