Python Solution
\nclass Solution:\n    def largestWordCount(self, messages: List[str], senders: List[str]) -> str:\n        d = defaultdict(list)\n        \n        for m, s in
```\nclass Solution:\n    def largestWordCount(self, messages: List[str], senders: List[str]) -> str:\n        d = defaultdict(list)\n        \n        for m, s in zip(messages, senders):\n            d[s].append(m)\n\n        longest = [0, []]\n        for s in d:\n            l = 0\n            for m in d[s]:\n                l += len(m.split())\n            if l > longest[0]:\n                longest[0] = l\n                longest[1] = [s]\n            elif l == longest[0]:\n                longest[1].append(s)\n                    \n        return max(longest[1])\n```
['Python3']