There can be several reasons why some people may pronounce voiced sounds as voiceless sounds. Here are a few possible explanations:
Accent or regional dialect: Different accents and dialects may have variations in pronunciation, including the distinction between voiced and voiceless sounds. Some accents or dialects may not make a clear distinction between certain voiced and voiceless sounds, leading to them being pronounced similarly or incorrectly.
Second language acquisition: For individuals who are learning a second language, they may carry over pronunciation patterns from their native language, where the distinction between voiced and voiceless sounds may be different. This can result in pronouncing voiced sounds as voiceless sounds or vice versa.
Articulation difficulties: Some individuals may have difficulties with speech articulation, known as speech sound disorders. In such cases, they may struggle with accurately producing specific sounds, including voiced sounds. This can lead to the substitution of voiceless sounds for voiced sounds.
Lack of awareness or training: Pronunciation is a skill that can vary from person to person. Some individuals may not have received formal training or instruction in proper pronunciation, which can result in mispronouncing certain sounds, including voiced sounds.
It's important to note that pronunciation variations are natural and can be influenced by a variety of factors. Communication is generally focused on conveying meaning, and slight pronunciation differences typically do not hinder understanding. However, in certain contexts, such as formal presentations or language proficiency assessments, clearer pronunciation may be necessary.
If you're concerned about your own pronunciation or wish to improve your skills, you can consider working with a speech-language pathologist or language instructor who can provide guidance and exercises to help refine your pronunciation.