English Language Proficiency Assessment Platform with AI Powered Suggestions for Evaluators to Consider

I'm seeking a professional to develop a secure assessment platform tailored for English language proficiency evaluations. The assessment will cover all 4 domains of language: speaking, writing, listening, and reading. This platform should integrate advanced AI functionalities designed to assist with the writing assessment, covering aspects like grammar, content analysis, text organization, and more.

Key Requirements:
- The platform should be able to host various essay prompts, serving as a comprehensive evaluation tool for students' writing skills.
- The AI capabilities included on the teacher/evaluator side should include, but not be limited to: grammar and spell checks, content analysis, detection of language complexity, organization of text, noting specific and technical vocabulary, and sentence analysis.The AI feedback should help the evaluator make a final evaluation for the writing component.
- The platform should cater to three distinct user roles: students, teachers, and administrators. Each role should have tailored access and functionalities, allowing for a seamless and secure assessment process.

Ideal Skills and Experience:
- Proven experience in developing secure online assessment platforms.
- Proficiency in AI technology, particularly in the context of writing evaluations.
- Strong understanding of user interface design for different user roles.
- Excellent track record of delivering projects on time and within budget.