The example at the top of the slide shows the small tsu being used in katakana to lengthen the ‘t’ sound that follows it. This can be transcribed as ‘intanetto’.

The bottom example shows usage of other small versions of katakana characters. The transcription is ‘konpyuutingu’. In the first case the small ‘yu’ combines with the preceding ‘pi’ to produce ‘pyu’. In the second case the small ‘i’ is used with the preceding ‘te’ syllable to produce ‘ti’ – a sound that is not native to Japanese. (Their equivalent would be ‘chi’.)

The bottom example also shows the use of the han-dakuten and dakuten to turn ‘hi’ into ‘pi’ and ‘ku’ into ‘gu’.

There is also a lengthening mark that lengthens the ‘u’ sound before it.