A team is developing a sentiment analysis model for Welsh, a language with limited available training data. A project manager proposes fine-tuning a large multilingual model that was pre-trained exclusively on Mandarin Chinese and Japanese text. The manager's justification is that the vast amount of data from these high-resource languages will ensure a powerful base model, leading to strong performance on Welsh. Critique this justification. Is the manager's reasoning sound? Explain why or why not, based on the principles of knowledge transfer between languages.