Here's why:
Arbitrary Elements:
* Word formation: The specific sounds or letters used to form words often have no inherent connection to the meaning. For example, the word "cat" doesn't sound like a cat, and there's no logical reason why "cat" signifies a feline creature.
* Inflectional morphology: The way we mark grammatical features like tense, number, or case can vary greatly across languages and can seem arbitrary. For instance, English uses "-ed" for past tense, while French uses "-é" or "-er."
Structured and Non-Arbitrary Elements:
* Morphemes: Morphemes are the smallest units of meaning in language. While the specific sounds of morphemes might be arbitrary, their function is often predictable and structured. For example, the "-ing" suffix consistently denotes present continuous tense in English.
* Derivational morphology: This involves creating new words from existing ones. While the specific suffixes or prefixes used can vary, they often follow patterns and have consistent meanings. For example, "-ness" often turns an adjective into a noun (e.g., "happy" to "happiness").
* Regularity and patterns: Even in seemingly arbitrary aspects of morphology, there are often underlying patterns and rules. For instance, English plural formation (adding "-s" or "-es") follows specific rules, even though the choice of suffix is not inherently connected to the meaning of "plurality."
Conclusion:
Morphology is a complex system with both arbitrary and structured elements. It's not entirely arbitrary, as there are underlying rules and patterns that govern word formation and grammatical features. However, the specific sounds or forms used to convey meaning often lack an inherent logical connection, adding a degree of arbitrariness to the system.