For several years now, our research has focused on how the brain ages and reorganizes its language functions. Findings since 2021 show that difficulty finding the right words does not necessarily indicate an overall decline in memory or intelligence. Rather, it primarily reflects a gradual transformation in the strategies the brain uses to access language.

Contrary to popular belief, words do not fade from our memory as we age. Our knowledge generally remains very solid, and our vocabulary often continues to grow thanks to the experience we have accumulated over the years. What changes more is the speed at which the brain accesses this knowledge.

Speaking is an extremely sophisticated process

To understand this phenomenon, it is important to remember that speaking is an extremely sophisticated process. When we produce a word, the brain must first activate its meaning—for example, the idea of an object, a person, or an action—then retrieve its sound form before preparing to articulate it.

In our recent work on language aging, we distinguish two key dimensions in particular. The first is the semantic dimension—that is, the meaning of words, knowledge, and associations built up through experience. The second is the phonological dimension, which refers to the sounds used to pronounce words. For example, when you say the word “cat,” you first retrieve its mental representation from memory, then transform that representation into a series of sounds that make it possible to articulate the word.

As we age, the systems related to meaning remain particularly robust. However, accessing the exact sound form of words sometimes becomes less fluid, as it is more vulnerable to the effects of aging. In short, the brain does indeed retrieve the meaning of the word, but its phonological retrieval requires greater mobilization of cognitive resources. This is precisely what creates the sensation of a “word on the tip of one’s tongue.”

New Strategies

However, our research conducted since 2021 shows that the brain does not passively undergo these changes. On the contrary, it develops new coping strategies.

As rapid processing based on word sounds becomes less effective, the brain relies more heavily on semantic knowledge, context, and accumulated experience. Phonological and semantic mechanisms are not mutually exclusive and continue to function in tandem. However, the brain changes associated with healthy aging appear to gradually increase the contribution of semantic systems, which then help compensate for phonological weaknesses.

In other words, when direct access to a word becomes more difficult, the brain compensates by drawing more heavily on meaning and associations. This reorganization is also accompanied by greater involvement of systems related to attention and the sensory organs, which help select relevant information.

Our most recent research shows that these adaptations do not apply solely to language itself. They reflect a more interactive reorganization of brain function as we age, which affects memory and attention in particular.

Starting around age 55, we observe gradual changes in the brain networks involved in language and communication. This reorganization is also evident at the level of brain networks. Recent studies using magnetoencephalography (MEG) suggest, in particular, that the brain tends to group semantic representations into larger, more stable units by associating them with visual or motor representations. To return to our example, the processing of the word “cat”—from its retrieval from memory to its articulation—would be mediated more by images, sounds, or movements to facilitate language.

Our research, conducted over the past three years, also suggests that these changes are part of a broader energy-saving strategy in the brain. As we age, certain long and energy-intensive neural connections—such as those in the phonological system—become more vulnerable. In response, the brain tends to favor more localized, energy-efficient circuits—criteria that systems related to meaning and experience appear to meet.

Brain aging thus appears less as a sudden decline than as a constant search for a balance between processing efficiency and energy conservation.

Cognitive Reserve

It is also important to note that this development varies greatly from one individual to another. Some people maintain a high level of verbal fluency well into old age, while others experience difficulties at an earlier stage. Some of these differences are related to what neuroscience refers to as cognitive reserve.

Cognitive reserve refers to the brain’s ability to adapt to change and draw on alternative strategies. It is influenced by many factors, such as educational level, intellectual activities, social interactions, physical activity, and multilingualism. The greater the cognitive reserve, the more the brain appears capable of compensating for the effects of aging.

It is precisely this diversity of individual trajectories that we are studying today in order to better understand why some brains remain particularly adaptable as we age and to identify trajectories of vulnerability at an earlier stage through the use of artificial intelligence and brain network analysis.

This research is part of a broader shift in how we approach brain health. Today, research is increasingly focused on detecting early signs of vulnerability before more significant cognitive impairments emerge. For example, an increase in the sensation of having a “word on the tip of one’s tongue” precedes measurable cognitive difficulties in other cognitive domains. It is in this context that brain health centers are emerging, developing preventive approaches based on the early identification of individuals who may be experiencing a decline in their cognitive abilities, even though objective measures do not yet show any deficits in these functions.

In conclusion, during healthy cognitive aging, the word almost always comes back to mind eventually. And when it takes a little longer, that doesn’t necessarily mean the brain is losing its abilities. It may simply indicate that it is adjusting its strategies to continue functioning in a different way.