Answer:
For:
The theory goes to state that animals CAN have the capacity of and/or for language, like humans. If you think about it, we humans have also evolved from creatures, making and developing things with our own hands. From apes to homo sapiens, humans can (possibly) withstand any difficulty in their way, by creating a path of solutions.
For example: Animals, such like the:
Gorillas, monkeys, parrots, dogs, etc. are various types of species that have learned to listen and comprehend what, we, humans, tell them.
We should give credit to how they can not only evolve like we have, changing their forms, but also the idea or concept that animals will one day come to learn more on how to comprehend what we tell them. Development is key, and this can be the same case towards a(n) infant learning to read, speak, and write.
Against:
This can be stated, as many various animals do not particular speak our language, or may not even know what we are saying. As studies say, animals don't have a true language like humans, however they can communicate with each other by sounds and gestures, such like growling, fur is spiked up, snarling, barking, etc. Animals use this as a figure in order to express their feelings, and more. But this does not count as a figure of language. This is because, the definition of language is: To communicate through words/speech and writing. This is a dialectal system that allows to show our wording, and such. Moreover, animals cannot interpret their (human's) language by speaking, they can only imitate and memorize what they are told.
Making a(n) argument for and against:
You want to be able to understand both sides in order to know what you want to say without being biased. In a(n) argument, we should voice our sides through facts, and research, and should make way for any opposition when the other side is being told, as there could be counterexamples that could prove your statements otherwise.