This quote from the article suggests that mechanism involved is specifically linguistic:
"""
To determine if words were being automatically (and perhaps unconsciously) activated, the researchers added the following twist: they asked their Russian participants to perform a verbal task at the same time as making their perceptual discrimination. This condition eliminated the reaction time advantage of contrasting goluboy and siniy. However, a nonverbal task (a spatial task) could be done at the same time while retaining the goluboy/siniy advantage. The dual task variants indicated that the task of discriminating color patches was aided by silent activation of verbal categories.
"""
To determine if words were being automatically (and perhaps unconsciously) activated, the researchers added the following twist: they asked their Russian participants to perform a verbal task at the same time as making their perceptual discrimination. This condition eliminated the reaction time advantage of contrasting goluboy and siniy. However, a nonverbal task (a spatial task) could be done at the same time while retaining the goluboy/siniy advantage. The dual task variants indicated that the task of discriminating color patches was aided by silent activation of verbal categories.
"""