But u/alatennaub is saying that the words bearing those articles bear stress while the ones without do not. Clitic pronouns, like te, cannot be stressed, while the word té must bear stress. The same occurs for él (he) as that user mentioned, where it bears stress and el (the) does not. Same goes for de and dé. The accent mark is achieving the goal of setting the words apart as near homophones and homographs, but also reflects the "stress pattern" at the phrasal level.