Using elgg_get_excerpt, how to truncate on a word boundary for Unicode characters

How to truncate very long inputs by css ref. by Juho Jaakkola (sp. thanks to him) is a good solution in some cases but not suitable for breadcrumbs.
elgg_get_excerpt is needed for breadcrumbs but it apparently breaks Unicode characters

Using  elgg_get_excerpt, how to truncate  on a word boundary for Unicode characters?