I'm a graduated philologist from Madrid, Spain, native Castilian Spanish speaker. I have made previous creative and academic writings, essays, books on different genres, including illustrated children books for BrillKids and Supercoloring, with cartoons, animals and dinosaurs.
You could trust me and please send me at least an excerpt, one or a few pages of the non-profit illustrated children book translated to Spanish so I can look over and check if I find errors. I will send the text file back to you with my first suggestions highlighted in the document.
I will send my edition at the end of the week for review as I progress in proofreading the non-profit illustrated children book, regarding misprints, grammar mistakes, verbal tenses. I usually enjoy the plot, vocabulary nuances, colloquial words, idioms, spelling errors, false friends words, so I will give attention to spanish linguistics while proofreading the non-profit illustrated children book.
Even if you may not sell the illustrated children book on amazon or libraries since it is non-profit you could also get an ISBN: International Standard Book Number.
Thank you for reading my proposal.