And the word is ... longer!? Word lengths and word expansion in languages.
Quite simply, word length is the number of letters in a word. When applying this to a language, we commonly talk about the average word length across the language, or at least the most common set of words in a language. (in Linguistics: the most common set of corpora or text corpus sets).
It stands to reason that different languages have different average word lengths. This is commonly referred to as "word expansion".
This becomes very important when we have to translate content to another language, because it greatly impacts the destination layout, how the content is presented, accuracy of the content and so on. As a simple example, consider a case where you have a text field or text box on a PowerPoint slide. The field has English text and we need to translate to French. The translated content may not fit in this field due to the longer words of the target language. If this is not handled properly, we may end up with formatting and layout that looks ugly or unprofessional at best. We may even end up with text being omitted or truncated depending on how the layout (design) is handled.
In summary, for reasons of accuracy, consistency and professionalism, word length is very important in the translations industry!
Additional Reference: The data presented below shows word lengths for English and comparisons with some common languages. This was calculated based on "big data" analysis performed by Ravi Parikh (http://www.ravi.io/). As Ravi cautions, the numbers are derived are not based on language corpuses, but rather from word lists for the language.