The late William Burroughs once said, "Language is a virus from Outer Space." It is an odd infection indeed, and yet as common to humanity as to be one of its defining characteristics. After whatever initial struggles we go through learning to speak and then read, it becomes such a facility with most of us to learn and adapt language almost without any cognizance of our doing so. Even so -- we are still 'contained' within whatever language "infections" we are exposed to. Learning to speak English or German does not automatically give you the ability to understand Swahili or Chinese.
There are only so many perceptions that the human species can name and so much of our experiences are universally shared. This allows for the amazing (!) characteristic of language that it is for the most part capable of being translated. On the other hand, human cultures and ways of thinking and relating are so diverse as to render some turns of phrase and words as "untranslatable." This appear contradictory, but is immediately understandable -- especially with any who have cross-cultural experiences.
How do language and images come together? In a strange way, it's a lot like words and music. The picture seems most often to take the forefront of cognizance, while the words are more subliminal. Even when careful attention is paid to the graphic presentation of the fonts with which the words are displayed, the awareness the viewer has of the words and their content of meaning is usually secondary to the image itself in the audience's consciousness. Nonetheless the words indelibly color the meaning of the image and lock down the interpretation of it. In some ways this can be a limitation, but it also allows for greater clarity of intent. All-in-all the combination of words and images present a challenging set of media for the creative person to explore.