Yes you can do by providing other written evidence. You have to write an explanation and support documantion for your appeal.
If you believe that you can clearly demonstrate your level of proficiency through a written submission, follow the instructions as the following steps:
Your written submission must demonstrate your language proficiency in all four abilities: speaking, listening, reading and writing.
1- Your written submission must clearly detail all of the following:
o Your education and training in English or French;
o Your work experience in English or French; and
o Any other contexts in which you may wish to provide details on your use of English or French (such as the language spoken in the home or in social situations).
2- Gather documentation which supports the claims made in your submission and submit these documents with your immigration application. Supporting documents should include:
o Degrees, diplomas, certificates, transcripts of all education completed in English or French;
o Documentation that supports your work experience in English or French, such as letters from employers, pay stubs, samples of your work, etc.; and
Any other evidence that proves that you have spent considerable time speaking, listening, reading and writing an English or French speaking environment.