The simple search analyzer is a custom Fotoware Alto implementation that does not use ElasticsearchSettings, allowing us to define min and max grams created on indexing and token_chars, which are character classes to keep in the tokens. Elasticsearch splits on characters that don't belong to any of these classes. defaults. The custom analyzer uses a regex:

• Regex
  */"(\[^\\p\{L\}\\d\]+)|(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)|(?<=\[\\p\{L\}&&\[^\\p\{Lu\}\]\])(?=\\p\{Lu\})|(?<=\\p\{Lu\})(?=\\p\{Lu\}\[\\p\{L\}&&\[^\\p\{Lu\}\]\])"/*
• Outcome:
  • Lowercase / Uppercase
  • Digit / non-digit
  • Stemming
  • HTML Strip
• Examples
  • Fotoware Alto = Fotoware Alto, fotoware alto
  • Case Study = Case, Study, case, study

If you want to test the simple search analyzer, you can check your terms in a regex tester to see the outcome.

1. Open a regex checker
   1. regex101: build, test, and debug regex
   2. RegExr: Learn, Build, & Test RegEx
2. Add your term as a test string
3. Check the outcome

The no diacritics analyzer:

• only works for text fields
• strips diacritic characters, so when the text value is: Kovačić Mateo, you can search for “Kovačić Mateo” or “Kovacic Mateo”.

An example can be found in Elasticsearch documentation: ASCII folding token filter | Elasticsearch Guide [8.17] | Elastic

The path hierarchy analyzer will:

• Take a path found in a field (fotoware alto\platform\manual) and delimit the individual terms
• Example
  • fotoware alto\platform\manual = fotoware alto\platform\manual, fotoware alto\platform, manual
  • Products/Family/Industry = Products/Family, Products, Products/Family/Industry

You should only configure this analyzer if it is used via the API. The simple search in Fotoware Alto escapes Special Characters, and therefore, you won't find assets when searching for some of the tokens generated by this analyzer. 
An example can be found in Elastic Search Documentation: Path hierarchy tokenizer | Elasticsearch Guide [8.17] | Elastic

There are several language analyzers available for Elastic Search. Language analyzers prevent stemming from language-specific values and language-specific stopwords. 
Language analyzers | Elasticsearch Guide [8.17] | Elastic 
The current implementation uses the default Elasticsearch language analyzers listed in the link. We are using the default stop words and stemming rules, without any customization. Settings allow us to define min and max grams created on indexing and token_chars, which are character classes to keep in the tokens. Elasticsearch splits on characters that don't belong to any of these classes..

The starting point for exact substring matches was n-gram tokenization, which indexes all substrings of length n. The drawback of n-gram tokenization is the large amount of disk space it consumes. 
Best practice:

• Use ngram only if required - use carefully and not for every string

Settings allow to define min and max grams created on indexing and token_chars, which are characters classes to keep in the tokens, Elasticsearch splits on characters that don't belong to any of these classes. 
Example: Search "Raven"

• NGrams (splits term into tokens with one character):
• Rav
• Rave
• Raven
• ave
• aven
• Ven
• ...

Example: Search "Pegasus"

• NGrams (splits term into tokens with one character):
• Pegasus
• Degas

Examples are in Elasticsearch documentation:
N-gram tokenizer | Elasticsearch Guide [8.17] | Elastic

This tokenizer is very similar to nGram, but only keeps n-grams that start at the beginning of a token. Settings allow us to define min and max grams created on indexing and token_chars, which are character classes to keep in the tokens. Elasticsearch splits on characters that don't belong to any of these classes.

Examples are in Elasticsearch documentation:
Edge n-gram tokenizer | Elasticsearch Guide [8.17] | Elastic

Simple Analyzer: Simple analyzer | Elasticsearch Guide [8.17] | Elastic

No Diacritics: ASCII folding token filter | Elasticsearch Guide [8.17] | Elastic

Path Hierarchy: Path hierarchy tokenizer | Elasticsearch Guide [8.17] | Elastic

Language: Language analyzers | Elasticsearch Guide [8.17] | Elastic

NGram: N-gram tokenizer | Elasticsearch Guide [8.17] | Elastic

EdgeNgram: Edge n-gram tokenizer | Elasticsearch Guide [7.6] | Elastic