1. Syntax and Paradigm Approach: Elixir follows a functional programming paradigm, focusing on immutability and pure functions, while Rust adopts a multi-paradigm approach with a strong emphasis on safety and performance. Swift, on the other hand, is a multi-paradigm language that combines object-oriented, imperative, and functional programming styles.

2. Memory Management: Rust utilizes a unique ownership system with borrowing and lifetimes to ensure memory safety without requiring a garbage collector. Elixir, being a garbage-collected language, abstracts memory management from the developer. Swift uses Automatic Reference Counting (ARC) for managing memory, automatically deallocating objects when they are no longer needed.

3. Concurrency and Parallelism: Elixir leverages the actor model through its built-in concurrency model, making it easier to write parallel programs using lightweight processes. Rust offers a powerful threading model with zero-cost abstractions for achieving parallelism. Swift provides support for asynchronous programming with tools like Grand Central Dispatch and SwiftNIO.

4. Tooling and Ecosystem: Rust has a robust toolchain, including Cargo for package management, rustfmt for formatting, and clippy for linting, making it a seamless experience for developers. Elixir comes with Mix, a build tool that handles dependency management and project tasks efficiently. Swift is backed by Xcode, an Integrated Development Environment (IDE) with extensive features for iOS, macOS, watchOS, and tvOS development.

5. Learning Curve and Community Support: Rust is often praised for its comprehensive and well-documented resources, helping developers overcome the initial learning curve of its borrow checker and ownership system. Elixir has a supportive community that values collaboration and knowledge-sharing, making it easier for newcomers to get started with the language. Swift benefits from the Apple ecosystem, leading to a sizable community and a plethora of resources for iOS and macOS development.

6. Use Cases and Adoption: Rust is commonly used for systems programming, such as operating systems, game engines, and web browsers, where performance and safety are crucial. Elixir is ideal for building scalable and fault-tolerant distributed systems, taking advantage of its concurrency model. Swift is predominantly used for developing iOS, macOS, watchOS, and tvOS applications due to its seamless integration with Apple's platforms.

In Summary, Elixir, Rust, and Swift differ in their syntax and paradigms, memory management approaches, concurrency models, tooling ecosystems, community support, and preferred use cases.