To determine the correct answer to the question regarding the nature of 'classroom speech,' let us examine the provided options and eliminate those that do not align with the definition of classroom speech:

1. Mass medium: A mass medium refers to a means of communication that reaches a large audience, often involving technology such as television, radio, newspapers, or the internet. Classroom speech does not fall under this category because it is not meant to reach a wide audience but is intended for a specific group of students within the classroom.
2. Non-technical medium: This option accurately describes classroom speech. Non-technical medium implies communication that does not require specialized equipment or expertise to understand. Classroom speech is typically straightforward and uses everyday language to facilitate learning, thus making it a non-technical medium.
3. Unorganised medium: An unorganised medium suggests a lack of structure or planning in communication. Classroom speech is usually well-organised and structured to convey educational material effectively, so this option does not fit.
4. Technical medium: A technical medium involves the use of specialized language or technical jargon, often requiring specific knowledge to comprehend. Classroom speech, especially in primary or secondary education, tends to avoid complex technical language, instead focusing on clear and accessible communication.

Based on the analysis above, the correct answer is the option that defines classroom speech as a Non-technical medium.