Question: Looking for a private and secure way to improve my English writing skills, any recommendations?

If you want to write in English but need a tool that's private and secure, you should check out Grammarly. Grammarly is an AI-powered writing assistant that offers context-specific suggestions and can even generate text to help you draft your ideas more quickly and accurately. It's got features like contextual suggestions, plagiarism detection and citation formatting, and it doesn't sell your data or use it for advertising.

Another good option is Paperpal, an AI-powered academic writing assistant that improves language, grammar and tone. It's got real-time grammar checking, plagiarism detection and a paraphraser that maintains a formal voice. Paperpal also can translate academic documents into other languages and has ISO/IEC 27001:2013 certification for data security, so your documents are protected.

If you need something that works with multiple languages and dialects, LanguageTool is a powerful option. It's got grammar checking, tone suggestions and paraphrasing, and plugins for many writing tools and websites. It's available for individuals and teams, with a free version with limited abilities and a premium version with more advanced features.

Last, QuillBot offers a suite of AI-powered writing tools, including a paraphraser, grammar checker, plagiarism detector and translator. Its interface is designed to be easy to use for writers of all skill levels, and the Premium subscription adds more features. QuillBot also protects your writing with tools to prevent accidental plagiarism.