Assess your student by breaking up their English.
Where appropriate you can give an informal grade from 1 to 5 for each component of each relevant skill/language area. Note that this is more important for long courses and more academic students and certainly ‘over the top’ for a more casual one week General English/Culture course.
Speaking: Individual sounds, Intonation, Fluency and linking, Silence-filling hesitation sounds, Choice and range of vocabulary
Writing: Use of vocabulary and appropriate register, Use of structures and grammar, Linking sentences with suitable adverbs etc, Planning and organisation, Answering the question
Listening: Catching the general idea, Picking out particular info, Understanding what the speaker really means or intends, Appreciating moods and attitudes, Guessing vocabulary
Reading: Overall meaning, Skim reading for the gist, Scanning for particular information, Understanding of detail, Appreciating the tone of the writing
Vocabulary: Range, Style, Accuracy etc
Grammar: Use and formation of tenses, Questions, Punctuation, Phrasal verbs, Irregular verbs, Conditionals, Clauses, Verbs, Passive structures etc etc
At the end of each week, you can indicate improvement and areas that need more attention.