Final answer:
Emotional attachments and the use of language in religious and cultural practices are the key factors that encourage language retention, as opposed to individual achievements disconnected from community ties.
Step-by-step explanation:
The cultural factors that encourage language retention among speakers include having an emotional attachment to the home or heritage language, and the use of the language in cultural and religious ceremonies. These factors foster a connection and sense of identity that make speakers more likely to maintain and use their language. An emotional attachment can come from the language's role in personal and family relationships, while religious and cultural ceremonies can reinforce the language's relevance and importance within a community. On the other hand, places that place a greater emphasis on individual achievement over family or community ties might discourage the communal aspects of language retention.
Therefore, the answer to the question is D, which is 'A and B only' because the strongest encouragement for language retention comes from the connections to family, heritage, and shared cultural practices rather than individualistic values.